This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
FIELD
DAY
2012
Report of Progress 1070
Kansas State University
Agricultural Experiment
Station and Cooperative
Extension Service
SOUTHWEST
RESEARCH-EXTENSION
CENTER
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Robert (Bob) Gillen, Research Center Head
B.S., Colorado State University
Ph.D., Oregon State University
Dr. Gillen was appointed head of the Western Kansas Agricultural Research Centers (Colby,
Garden City, Hays, and Tribune) in 2006. His research interests include grazing management
systems, grassland ecology, and forage establishment.
Phil Sloderbeck, Southwest Area Extension Director
M.S., Purdue University
Ph.D., University of Kentucky
Phil joined the staff in 1981. His extension emphasis is insect pests of field crops.
Debra Bolton, Extension Specialist, Family and Consumer Sciences
B.S., English, St. Mary of the Plains College
M.S., Fort Hays State University
Ph.D., Kansas State University
Debra works with county agents on various projects, program development and training.
Her research focuses on families in their environments, rural social systems, and community
developmental processes.
Rod Buchele, Extension Specialist, 4-H Youth Development
B.S., Economics, Iowa State University
M.S., Guidance and Counseling, University of Wisconsin-Platteville
Rod joined the staff in fall of 2003 from Colorado State University Cooperative Extension.
He previous positions were with University of Florida Cooperative Extension and University
of Wisconsin Extension, all in 4-H Youth Development.
Randall Currie, Weed Scientist
B.S., Kansas State University
M.S., Oklahoma State University
Ph.D., Texas A&M University
Randall joined the staff in 1991. His research focus is on weed control in corn.
Troy Dumler, Extension Agricultural Economist
B.S., M.S., Kansas State University
Troy joined the staff in 1998. His extension program focuses primarily on crop production
and machinery economics.
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
FIELD
DAY
2012
Contents
III
2012 Southwest Research-Extension Center Staff
IV
2012 Support Personnel
1Weather
1
Weather Information for Garden City
3
Weather Information for Tribune
5
Cropping and Tillage Systems
5
Benefits of Long-Term No-till in a Wheat-Sorghum-Fallow
Rotation
7
Cover Crops Reduce Wind and Water Erosion
12
Cover Crop Forage Biomass Yield
18
Effect of Simulated Hail Damage on Corn Yield
24
Fallow Replacement Crop Effects on Wheat Yield
30
Four-Year Rotations with Wheat and Grain Sorghum
34
Soil Fertility
34
Nitrogen and Phosphorus Fertilization of Irrigated Corn
40
Nitrogen and Phosphorus Fertilization of Irrigated Grain
Sorghum
45
Phosphorus Fertilization of Irrigated Corn
47
Phosphorus Fertilization of Irrigated Grain Sorghum
I
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has been archived. Current information is available from http://www.ksre.ksu.edu.
49
Weed Science
49
Weed Control with 9 Tank Mixes of Saflufenacil,
Dimethenamid-P, Atrazine, and Pyroxasulfone Herbicide
in Irrigated Glyphosate-Resistant Corn
52
Weed Control with 15 Herbicide Tank Mixes of Isoxaflutole,
Tembotrione Thiencarbazone-methyl, Atrazine, Trileton,
S-metolachlor, and Mesotrione Herbicide in Irrigated
Glyphosate-Resistant Corn
55
Weed Control with 21 Tank Mixes of Rimsulfuron, Mesotrione,
and Atrazine and Isoxaflutole Herbicide in Irrigated GlyphosateResistant Corn
58
Reductions in Corn Leaf Area Induced by Drought Stress
and Level of Irrigation Impacts Weed Control
60
Kochia Seedling Emergence Patterns Across the Central
Great Plains
63
Alternatives to Glyphosate for Kochia Control in Dryland
No-Till Corn
66
Regional Studies on Kochia Management without Glyphosate
69Acknowledgments
70
II
Herbicide Premix Appendix
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
2012 Southwest Research-Extension Center Staff
Robert Gillen
Head
Phil Sloderbeck
Area Extension Director
Conall Addison
Instructor Emeritus
Debra Bolton
Extension Specialist, Family Consumer Sciences
Dewayne Bond
Assistant Scientist
Rod Buchele
Extension Specialist, 4-H Youth Development
Larry Buschman
Corn Entomologist Emeritus
Randall Currie
Weed Scientist and Associate Professor
Troy Dumler
Extension Agricultural Economist
Jeff Elliott
Research Farm Manager
Gerald Greene
Professor Emeritus
George Herron
Professor Emeritus
Johnathon Holman
Associate Professor
Jennifer Jester
Assistant Scientist
Norman Klocke
Irrigation Engineer
Ray Mann
Professor Emeritus
Bertha Mendoza
EFNEP/FNP Area Agent
Charles Norwood
Professor Emeritus
Tom Roberts
Assistant Scientist
Alan Schlegel
Agronomist-in-Charge, Tribune
Justin Waggoner
Extension Specialist, Animal Production
Assistant Professor
Carol Young
Associate Professor Emeritus
III
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
2012 Support Personnel
Ashlee Wood
Administrative Specialist
David Bowen
Agricultural Technician Senior
Norma Cantu
Senior Administrative Assistant
Manuel Garcia
Gen. Maintenance and Repair Technician II
Lynn Harshbarger
Administrative Specialist
Jaylen Koehn
Agricultural Technician Senior
Scott Maxwell
Agricultural Technician Senior
Joanna Meier
Accountant I
Dale Nolan
Agricultural Technician Senior, Tribune
David Romero, Jr.
Equipment Mechanic
Ramon Servantez
Agricultural Technician Senior
Jeff Slattery
Agricultural Technician Senior, Tribune
Monty Spangler
Agricultural Technician Senior
Dennis Tomsicek
Agricultural Technician Senior
Southwest Research-Extension Center
4500 East Mary, Bldg. 947
Garden City, KS 67846
Phone: 620-276-8286
Fax: 620-276-6028
IV
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Weather
Weather Information for Garden City
J. Elliott
Precipitation for 2011 totaled 12.12 in. This was 7.12 in. below the 30-year average
of 19.24 in. Each month, with the exception of April and December, recorded belowaverage moisture. The year 2011 was ranked the 15th driest since our records began 103
years ago. The largest precipitation event was 1.20 in. of rain/snow on December 20.
Pea-size hail was noted on May 25.
Measureable snowfall occurred in January, February, March, and December 2011.
Annual snowfall totaled 17.2 in. The 30-year average is 19.7 in. The largest event was 8.0
in. of wet snow recorded on December 20. Seasonal snowfall (2010–2011) was
9.5 in.
Average daily wind speed was 4.65 mph. The 30-year average is 5.10 mph. Open-pan
evaporation from April through October was 89.03 in., which is 18.77 in. above the
30-year mean. Notably, evaporation totaled more than 10 times precipitation for the
same 7-month period.
In addition to the dry conditions, the other story of 2011 was the heat. Triple-digit
temperatures were observed on 45 days in 2011, with the highest being 109°F on
June 30. Ten record-high temperatures were equaled or exceeded in 2011: 81°F on
February 17, 91°F on March 5, 93°F on March 10, 102°F on May 30, 107°F on June
27, 109°F on June 30, 108°F on July 21, 106°F on July 28, 105°F on August 19, and
106°F on August 24. Sub-zero temperatures occurred 11 times in 2011, and the lowest
temperature, -13°F, was recorded on February 10. Two record-low temperatures were
set in 2011, -8°F on January 13 and -13°F on February 10.
The last spring freeze was 32°F on May 16, which is 17 days later than the 30-year average. The first fall freeze was 32°F on October 18, which is 6 days later than normal. This
resulted in a 155-day frost-free period, which is 10 days shorter than the 30-year average.
The 2011 climate information for Garden City is summarized in Table 1.
1
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
2
Normal latest spring freeze (32°F): April 29. In 2011: May 16.
Normal earliest fall freeze (32°F): October 12. In 2011: October 18.
Normal frost-free period (>32°F): 165 days. In 2011: 155 days.
30-year averages are for the period 1981–2010. All recordings were taken at 8:00 a.m.
Wind
30-year
2011
avg.
------mph------3.09
4.50
4.57
5.24
5.04
6.31
5.88
6.42
5.83
5.76
5.72
5.37
4.50
4.59
3.95
4.11
3.83
4.73
4.83
4.89
4.71
4.80
3.86
4.45
4.65
5.10
Evaporation
30-year
2011
avg.
---------in.---------------9.74
8.21
12.79
10.04
16.09
11.96
18.17
13.22
14.03
11.28
10.12
9.22
8.09
6.33
----89.03
70.26
Weather
Table 1. Climate data, Southwest Research-Extension Center, Garden City
Monthly temperatures
Precipitation
2011 avg.
2011 extreme
30-year
Month
2011
avg.
Max
Min
Mean
avg.
Max
Min
--------in.-----------------------------------------°F---------------------------------January
0.18
0.46
44.3
12.8
28.5
30.4
71
-9
February
0.43
0.55
47.5
12.0
29.7
33.9
81
-13
March
0.66
1.31
57.1
26.9
42.0
42.9
84
10
April
1.79
1.74
70.7
36.9
53.8
52.3
93
26
May
1.14
2.98
78.4
44.0
61.2
62.8
102
29
June
1.69
3.12
93.3
59.8
76.6
72.6
109
48
July
0.54
2.80
101.3
68.5
84.9
77.9
108
65
August
2.43
2.51
98.1
65.9
82.0
76.3
106
60
September
0.37
1.42
83.4
49.4
66.4
67.7
105
36
October
0.44
1.21
72.5
39.8
56.1
54.9
95
25
November
0.42
0.55
57.1
26.0
41.6
41.6
79
15
December
2.03
0.59
39.9
16.5
28.2
31.4
62
0
Annual
12.12
19.24
70.3
38.2
54.3
53.7
109
-13
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Weather
Weather Information for Tribune
D. Bond and D. Nolan
Total yearly precipitation was 22.93 in., which is 5.03 in. above normal. Seven months
had above-normal precipitation. July (5.15 in.) was the wettest month. The largest
single amount of precipitation was 3.11 in. on June 21. January was the driest month
(0.33 in.). Snowfall for the year totaled 33.0 in.; January, February, March, November,
and December had 3.7, 7.7, 5.0, 1.6, and 15.0 in., respectively, for a total of 44 days
of snow cover. The longest consecutive period of snow cover, 12 days, occurred
December 20 through 31.
Record high temperatures were recorded on five days: March 22 (85°F), April 3 (89°F),
April 4 (87°F), June 6 (101°F), and June 7 (101°F). Record high temperatures were tied
on May 31 (97°F) and October 4 (94°F). No record low temperatures were recorded,
but a record low temperature was tied on May 31 (37°F). July was the warmest month
with a mean temperature of 80.9°F. The hottest days of the year (103°F) occurred on
June 30; July 1 and 20; and August 24. The coldest day of the year (-14°F) was January
11. December was the coldest month with a mean temperature of 28.0°F.
Mean air temperature was above normal for seven months. July had the greatest departure above normal (4.2°F), and February had the greatest departure below normal
(-3.5°F). Temperatures were 100°F or higher on 22 days, which is 11 days above normal.
Temperatures were 90°F or higher on 79 days, which is 16 days above normal. The latest
spring freeze was May 16, which is 10 days later than the normal date, and the earliest
fall freeze was October 19, which is 12 day later than the normal date. This produced a
frost-free period of 156 days, which is 2 days more than the normal of 154 days.
Open-pan evaporation from April through September totaled 76.50 in., which is
5.10 in. above normal. Wind speed for this period averaged 4.8 mph, which is 0.5 mph
less than normal.
A summary of the 2011 climate information for Tribune is presented in Table 1.
3
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has been archived. Current information is available from http://www.ksre.ksu.edu.
4
Normal latest freeze (32°F) in spring: May 6. In 2011: May 16.
Normal earliest freeze (32°F) in fall: Oct. 7. In 2011: October 19.
Normal frost-free (>32°F) period: 154 days. In 2011: 156 days.
Normal for precipitation and temperature is 30-year average (1981–2010) from the National Weather Service.
Normal for latest freeze, earliest freeze, wind, and evaporation is 30-year average (1981–2010) from Tribune weather data.
Wind (mph)
2011
Normal
------------5.7
6.0
6.0
5.6
5.5
5.2
4.4
5.2
3.8
4.7
3.2
5.0
------------4.8
5.3
Evaporation (in.)
2011
Normal
------------9.37
8.27
14.21
11.75
15.96
14.04
16.90
15.58
12.01
12.16
8.05
9.60
------------76.50
71.40
Weather
Table 1. Climatic data, Southwest Research-Extension Center, Tribune
Monthly average temperatures (°F)
Precipitation (in.)
2011
Normal
2011 extreme
Month
2011
Normal
Max
Min
Max
Min
Max
Min
January
0.33
0.49
44.5
13.3
44.0
16.2
72
-14
February
0.69
0.52
46.4
13.7
47.5
19.4
77
-12
March
0.88
1.22
57.6
25.9
56.3
26.8
85
11
April
1.36
1.45
68.9
36.2
65.7
34.9
89
22
May
0.80
2.38
76.5
43.8
75.1
46.4
100
28
June
4.80
2.94
90.3
58.2
85.7
56.6
103
49
July
5.15
2.85
96.7
65.1
91.8
61.7
103
58
August
3.40
2.33
93.7
63.5
89.4
60.4
103
58
September
0.95
1.18
79.8
49.1
81.5
50.6
102
35
October
2.53
1.49
70.3
38.7
68.9
37.1
94
23
November
0.63
0.55
56.2
25.5
54.9
25.7
75
14
December
1.41
0.50
39.9
16.0
44.7
17.0
61
-6
Annual
22.93
17.90
68.5
37.6
67.1
37.7
103
-14
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has been archived. Current information is available from http://www.ksre.ksu.edu.
Cropping and Tillage Systems
Benefits of Long-Term No-till in a WheatSorghum-Fallow Rotation1
A. Schlegel, L. Stone2, and T. Dumler
Summary
Grain yields of wheat and grain sorghum increased with decreased tillage intensity in a
wheat-sorghum-fallow (WSF) rotation. Averaged over the past 11 years, no-till (NT)
wheat yields were 6 bu/a greater than reduced tillage and 9 bu/a greater than conventional tillage. Grain sorghum yields in 2011 were 35 bu/a greater with long-term NT
than short-term NT. Averaged across the past 11 years, sorghum yields with long-term
NT have been twice as great as short-term NT (62 vs. 31 bu/a).
Procedures
Research on different tillage intensities in a WSF rotation at the Tribune Unit of the
Southwest Research-Extension Center was initiated in 1991. The three tillage intensities in this study are conventional (CT), reduced (RT), and no-till (NT). The CT
system was tilled as needed to control weed growth during the fallow period. On average, this resulted in four to five tillage operations per year, usually with a blade plow or
field cultivator. The RT system originally used a combination of herbicides (one to two
spray operations) and tillage (two to three tillage operations) to control weed growth
during the fallow period; however, in 2001, the RT system was changed to using NT
from wheat harvest through sorghum planting (short-term NT) and CT from sorghum
harvest through wheat planting. The NT system exclusively used herbicides to control
weed growth during the fallow period. All tillage systems used herbicides for in-crop
weed control.
Results and Discussion
Since 2001, wheat yields have been severely depressed in 6 of 11 years, primarily because
of lack of precipitation. Reduced tillage and no-till increased wheat yields (Table 1). On
average, wheat yields were 9 bu/a higher for NT (25 bu/a) than CT (16 bu/a). Wheat
yields for RT were 3 bu/a greater than CT even though both systems had tillage prior
to wheat. NT yields were less than CT or RT in only 1 of the 11 years.
The yield benefit from RT was greater for grain sorghum than wheat. Grain sorghum
yields for RT averaged 13 bu/a more than CT, whereas NT averaged 31 bu/a more
than RT (Table 2). For sorghum, both RT and NT used herbicides for weed control
during fallow, so the difference in yield could be attributed to short-term compared
with long-term no-till. In 2011, sorghum yields were 35 bu/a greater with long-term
NT than short-term NT. This consistent yield benefit with long-term vs. short-term
NT has been observed since the RT system was changed in 2001. Averaged across the
past 11 years, sorghum yields with long-term NT have been twice as great as short-term
NT (62 vs. 31 bu/a).
1
2
This research project was partially supported by the Ogallala Aquifer Initiative.
Kansas State University Department of Agronomy.
5
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has been archived. Current information is available from http://www.ksre.ksu.edu.
Cropping and Tillage Systems
Table 1. Wheat response to tillage in a wheat-sorghum-fallow rotation, Tribune,
2001–2011
Tillage
ANOVA (P > F)
LSD
Tillage ×
Year
Conventional Reduced
No-till
(0.05)
Tillage
Year
year
------------- bu/a ------------2001
17
40
31
8
0.002
2002
0
0
0
----2003
22
15
30
7
0.007
2004
1
2
4
2
0.001
2005
32
32
39
12
0.360
2006
0
2
16
6
0.001
2007
26
36
51
15
0.017
2008
21
19
9
14
0.142
2009
8
10
22
9
0.018
2010
29
35
50
8
0.002
2011
22
20
20
7
0.649
Mean
16
19
25
2
0.001
0.001
0.001
Table 2. Grain sorghum response to tillage in a wheat-sorghum-fallow rotation,
Tribune, 2001–2011
Tillage
ANOVA (P > F)
LSD
Tillage ×
Year
Conventional Reduced
No-till
(0.05)
Tillage
Year
year
------------- bu/a ------------2001
6
43
64
7
0.001
2002
0
0
0
----2003
7
7
37
8
0.001
2004
44
67
118
14
0.001
2005
28
38
61
35
0.130
2006
4
3
29
10
0.001
2007
26
43
62
42
0.196
2008
16
25
40
20
0.071
2009
19
5
72
31
0.004
2010
10
26
84
9
0.001
2011
37
78
113
10
0.001
Mean
18
31
62
5
0.001
0.001
0.001
6
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Cropping and Tillage Systems
Cover Crops Reduce Wind and Water Erosion
H. Blanco and J. Holman
Summary
We studied the impacts of various cover crops on wind and water erosion under a
no-till, wheat-fallow rotation at the Southwest Research-Extension Center in Garden
City, KS, after five years of cover crop establishment. Cover crops generally reduced
wind and water erosion. Spring lentil cover crop reduced soil’s susceptibility to wind
erosion, whereas spring pea and winter triticale reduced runoff and loss of sediment and
nutrients compared with fallow. Results also indicated that haying of cover crops may
not affect wind erosion risks in the short term. Overall, cover crops can conserve soil by
reducing wind and water erosion in this semiarid climate.
Introduction
Growing annual forages or cover crops in place of fallow in a wheat-fallow system is a
farming practice that may potentially conserve and improve soil resources. Cover crops
may particularly help to reduce wind and water erosion in semiarid regions such as the
central Great Plains. Winter wheat-fallow rotation is a dominant cropping system in
the region. This rotation is, however, highly vulnerable to wind erosion and soil quality
degradation during the fallow phase due to reduced residue cover.
Although wind erosion is often a greater concern than water erosion in semiarid
regions, water erosion from crop-fallow systems also can be significant. The limited
precipitation in the semiarid Great Plains often occurs in the form of intense and localized rainstorms, which can cause large seasonal losses of soil and nutrients in runoff.
Cover crops are attracting attention, but the extent to which cover crops reduce water
and wind erosion in semiarid regions is not well understood. Some producers want
to grow annual forages in place of fallow rather than a cover crop; however, harvesting forages reduces the amount of residue left on the soil surface and might reduce
soil erosion and improve soil quality less than cover crops. Thus, the effects of annual
forages and cover crops on soil erosion need to be determined. This study assessed the
effects of both annual forages and cover crops on wind and water erosion for a no-till,
wheat-fallow rotation.
Procedures
We studied wheat-fallow rotation managed with a number of cover crops and annual
forages under no-till for five years at the Southwest Research-Extension Center. Within
the fallow phase, treatment plots consisted of chemical fallow, winter crops (hairy
vetch, winter lentil, Austrian winter pea, winter triticale, and each winter legume
combined with winter triticale), spring crops (spring lentil, spring field pea, spring
triticale, and each spring legume combined with spring triticale), winter and spring peas
grown for grain, and continuous winter wheat. Each plot was split in two, with half the
plot managed under cover crops (non-hayed) and the other half under annual forage
(hayed.) The treatments were replicated three times in a randomized complete block
design.
7
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Cropping and Tillage Systems
For the study of wind erosion, seven treatments, including fallow (control), winter
lentil, spring pea, spring lentil, winter triticale, spring triticale, and continuous winter
wheat, were selected from the larger experiment. To study the effects of cover crop
haying on wind erosion, winter triticale and spring triticale with half the plot managed
under cover crops (non-hayed) and the other half under annual forage (hayed) were
selected. For the study of water erosion, five cover crop treatments including fallow
(control), winter lentil, spring triticale, spring pea, and winter triticale were selected.
Two soil parameters that directly influence the soil’s susceptibility to wind erosion,
wind-erodible fraction of the soil and aggregate size expressed as geometric mean diameter of dry aggregates, were used to evaluate wind erosion. About 5 lb of soil sample
were collected from the 0- to 2-in. depth from the 10 treatments in August 2011. The
soil samples were oven-dried at 56°C for 48 hours and passed through a rotary sieve.
Soil aggregates using the rotary sieve method were classified into different aggregate-size
fractions as follows: <0.42, 0.42 to 0.84, 0.84 to 2, 2 to 6.35, 6.35 to 14.05, 14.05 to
44.45, and >44.45 mm in diameter. Wind-erodible fraction was computed as the fraction of soil aggregates with diameter <0.84 mm. The different aggregate-size fractions
were used to compute the geometric mean diameter of dry aggregates.
Water erosion was measured using a rainfall simulator in August 2011. A solenoidoperated and single-nozzle rainfall simulator was used. Small 3-ft × 6-ft runoff plots
were established within the larger cover crop plots. Rainfall was applied for 1 hour
to each plot at 3 in./hour, representing a five-year rainfall return period for the study
region. Runoff volume was measured and runoff samples were collected for the determination of sediment and nutrient (nitrogen [N] and phosphorus [P]) concentrations.
Results and Discussion
Wind erosion
Replacing fallow with cover crops affected all soil erodibility properties. Cover crops
generally reduced the wind-erodible fraction of the soil and increased the size of aggregates compared with fallow. For example, spring lentil reduced the erodible fraction
by 73% (Figure 1A) and increased geometric mean diameter of dry aggregates by 65%
compared with fallow (Figure 1B). These results indicate that replacing fallow with a
crop increased soil macroaggregation. The larger the aggregates, the lower the aggregate
breakdown and the lower the soil’s susceptibility to wind erosion. Results also suggest
that the effects of cover crops on reducing wind erosion depend on cover crop species.
Effects of harvesting an annual forage compared with growing a cover crop on wind
erosion were not significant (Figures 1A and 1B). Although haying of winter and spring
triticale increased the wind-erodible fraction and reduced aggregate size relative to
winter and spring triticale without haying, differences were not statistically significant
due to the high variability in data. Based on the trend for increased wind erosion with
haying, we suggest that haying of cover crops may significantly increase wind erosion
crops in the long term.
Continuous wheat also reduced erodible fraction (Figure 1A) and increased geometric
diameter of aggregates (Figure 1B) relative to fallow. Annual straw input and perma8
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Cropping and Tillage Systems
nent straw cover may be the reasons for the greater ability of continuous wheat to
reduce wind erosion.
Water erosion
The five selected cover crop treatments also affected water erosion. Cover crops reduced
water erosion, but the effects were significant only at the 0.10 statistical probability
level. This result suggests that cover crops may have more beneficial effects on reducing
wind erosion than water erosion in this soil with moderate slopes (<3%). Cover crops
generally reduced runoff (Figure 2A), sediment loss (Figure 2B), and loss of sedimentassociated total P and nitrates (NO3-N). Winter triticale, spring pea, and spring triticale
had large effects and reduced runoff by 350% relative to fallow (Figure 2A). Winter
triticale and spring pea reduced sediment loss by 370%, but winter lentil and spring
triticale had no effects (Figure 2B). Winter triticale and spring pea reduced losses of
total P and NO3-N by 380% compared with fallow.
Results show that 60% of simulated rain was lost as runoff from plots without cover
crops, and only about 13% was lost from plots with winter triticale, spring pea, and
spring triticale cover crops. Winter triticale and spring pea cover crops reduced sediment loss by about 0.53 tons/a under a single and simulated rainfall event at 3 in./hour.
Winter triticale appeared to be the most effective cover crop treatment for reducing
runoff and loss of sediment and nutrients.
Conclusions
Results from this study showed that cover crops reduced wind and water erosion in a
no-till, wheat-fallow rotation in this semiarid region. In general, the wind-erodible fraction of the soil was lower and soil aggregates were larger when cover crops were included
in the wheat-fallow rotation. Similarly, runoff and sediment loss were reduced with the
inclusion of cover crops. Winter triticale and spring pea cover crops were particularly
effective for reducing runoff and sediment loss. Our study also showed that continuous wheat was effective to reduce wind erosion risks compared with fallow. Haying of
winter and spring triticale appears not to have significant effects on wind erosion in the
short term. Long-term (>5 years) monitoring is needed to determine conclusively
the effects of cover crop haying on wind erosion and other soil and environmental
parameters.
The use of cover crops in semiarid regions has been questioned because cover crops use
water and may thus reduce plant-available water for the subsequent crops. Our results
suggest that cover crops may contribute to water storage by reducing runoff, which
may somewhat reduce the negative effects of cover crops on soil water storage for the
subsequent crops. Selection of the most suitable or drought-tolerant species and development of improved management strategies (i.e., early termination) may reduce the
adverse effects of cover crops on water storage.
9
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Cropping and Tillage Systems
Wind-erodible fraction
0.8
A
Hayed
A
a
0.6
ab
0.4
ab
b
Aab A
Aab
b
0.2
0
Geometric mean diameter
of dry aggregates, mm
2.0
B
1.6
Aa
ab
ab
1.2
a
a
b
Aab
A
A
0.8
0.4
0
Fallow
Winter
lentil
Spring
lentil
Spring
pea
Winter
triticale
Spring Continuous
triticale
wheat
Figure 1. Impact of cover crops on the (A) wind-erodible fraction (<0.84 mm aggregates)
of the soil and (B) dry aggregate size expressed as geometric mean diameter of aggregates.
Means with the same lowercase letter are not significantly different. Means with the same
uppercase letter for hayed (white bars) and non-hayed (black bars) winter and spring triticale are not statistically different at P = 0.10.
10
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Cropping and Tillage Systems
Runoff depth, in.
2.0
A
a
1.5
ab
1.0
b
b
0.5
b
0
Sediment loss, tons/a
1.00
0.75
B
a
0.50
ab
ab
0.25
b
b
0
Fallow
Winter
lentil
Spring
triticale
Spring
pea
Winter
triticale
Figure 2. Impact of cover crops on runoff and sediment loss. Means or bars with the same
lowercase letter are not statistically different at P = 0.10.
11
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Cropping and Tillage Systems
Cover Crop Forage Biomass Yield
J. Holman, T. Dumler, T. Roberts, and S. Maxwell
Summary
Producers are interested in growing cover crops or annual forages in place of fallow. A
study was initiated in 2007 to evaluate several crops grown in place of fallow in a no-till
wheat-fallow system. Crops that produce more biomass may be the best cover crop and
forage crop. Cover crops that produce the most biomass may also have the least amount
of wind and water soil erosion and the greatest impact on soil carbon (C). Forage crops
that produce the most biomass may be the most profitable to grow. Winter triticale
produced the most yield, spring triticale and spring pea produced the second most yield,
and all other crops yielded less.
Introduction
Interest in growing cover crops and replacing fallow with a cash crop has necessitated
research on species that are adapted to southwest Kansas and their forage biomass
potential. Fallow stores moisture, which helps stabilize crop yields and reduce the risk
of crop failure; however, only 25 to 30% of the precipitation received during the fallow
period of a no-till wheat-fallow rotation is stored. The remaining 70 to 85% precipitation is lost primarily to evaporation. Moisture storage in fallow is more efficient earlier
in the fallow period when the soil is dry and during the winter months when the
evaporation rate is lower. Increasing cropping intensity without reducing winter wheat
yield may be possible. Growing a cover crop that produces a lot of biomass may reduce
evaporation; in contrast, evaporation may be greater following a cover crop harvested
for forage. This study evaluated the forage biomass yield of several winter and spring
crops.
Procedures
Fallow replacement crops (cover, annual forage, or short-season grain crops) have been
grown during the fallow period of a no-till wheat-fallow cropping system every year
since 2007. Crops were either grown as cover, harvested for forage (annual forage crop),
or harvested for grain. Both winter and spring crop species were evaluated. Winter
species included yellow sweet clover (Melilotus officinalis (L.) Lam.), hairy vetch (Vicia
villosa Roth ssp.), lentil (Lens culinaris Medik.), Austrian winter forage pea (Pisum sativum L. ssp.), Austrian winter grain pea (Pisum sativum L. ssp.), and triticale (×Triticosecale Wittm.). Spring species included lentil (Lens culinaris Medik.), forage pea (Pisum
sativum L. ssp.), grain pea (Pisum sativum L. ssp.), and triticale (×Triticosecale Wittm.).
Crops were grown in monoculture and in two-species mixtures of each legume plus
triticale. Crops grown for grain were grown in monoculture only. Winter lentil was
grown in place of yellow sweet clover beginning in 2009. Crops grown in place of fallow
were compared with a wheat-fallow and continuous wheat rotation for a total of
16 treatments (Table 1). The study design was a split-split-plot randomized complete
block design with 4 replications; crop phase (wheat-fallow) was the main plot, fallow
replacement was the split-plot, and fallow replacement method (forage, grain, or cover)
was the split-split-plot. The main plot was 480 ft wide and 120 ft long, the split plot was
30 ft wide and 120 ft long, and the split-split plot was 15 ft wide and 120 ft long.
12
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Cropping and Tillage Systems
Winter crops were planted approximately October 1. Winter cover and forage crops
were chemically terminated or forage harvested approximately May 15. Spring crops
were planted between the end of February and middle of March. Spring cover and
forage crops were chemically terminated or forage harvested approximately June 1.
Forage biomass yield for both cover crop and forage crop was determined from a 3-ft
by 120-ft area cut 3 in. high using a small-plot Carter forage harvester from within the
split-split-plot managed for forage. Winter and spring grain peas and winter wheat
were harvested with a small plot combine from a 6.5-ft by 120-ft area at grain maturity,
which occured approximately the first week of July.
Volumetric soil moisture content was measured at cover crop termination and winter
wheat planting using a Giddings Soil Probe (Giddings Machine Company, Windsor,
CO) to a 6-ft soil depth. Grain yield was adjusted to 13.5% moisture content and test
weight was measured using a grain analysis computer. Grain samples were analyzed for
nitrogen content. Forage samples were weighed wet, then a homogenized subsample
was collected, dried at 50ºC in a forced-air oven for 96 h, weighed dry for dry matter
yield, and sent to a commercial laboratory for crude protein (CP), acid detergent fiber
(ADF), and neutral detergent fiber (NDF) determination.
Results and Discussion
Forage yield of crop species varied by year due to differences in winter survival and
moisture conditions. Winter species (2,336 lb/a) tended to yield more than spring
species (1,493 lb/a), although there were differences between years (P = 0.003) (Figure
1). Forage yield data from 2007 was not included in the analysis since previous land area
management might have caused variation in yield. Forage yield data from 2008 through
2011 were analyzed. Yellow sweet clover did not produce any harvestable biomass in
2007 or 2008 and was replaced with winter lentil beginning in 2009.
In 2008, yields of winter (2,712 lb/a) and spring crops (2,030 lb/a) did not differ
(P = 0.08), and all winter crops survived the winter (Figure 2). Winter pea showed
some visual sign of winter injury, but all other winter crops survived the winter without
injury symptoms. Treatments that included winter triticale yielded the most, and treatments with spring triticale yielded the second most. Spring pea, hairy vetch, winter pea,
and spring lentil yielded the least. Yellow sweet clover did not produce any harvestable
biomass (data not shown).
In 2009, winter crops (2,708 lb/a) yielded more than spring crops (1,296 lb/a) (Figure
3). Winter stand loss was estimated at 50% for winter pea and 95% for hairy vetch.
Winter lentil showed no signs of winter injury. Winter survival of winter pea and hairy
vetch was greater when grown in mixture with winter triticale than in monoculture.
Treatments with winter triticale yielded the most. Winter pea/triticale (5,220 lb/a)
yielded more than hairy vetch/triticale (4,503 lb/a) or winter lentil/triticale (3,703 lb/a),
which was likely due to the winter peas adding to the yield of triticale grown alone
(4,726 lb/a). Treatments with spring triticale yielded the second most, ranging from
1,266 to 1,815 lb/a, which did not differ from spring peas grown alone (1,467 lb/a).
Winter pea, spring lentil, and winter lentil yielded the least. Hairy vetch did not yield
any harvestable biomass due to winter-kill.
13
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Cropping and Tillage Systems
In 2010, winter crops (3,018 lb/a) yielded more than spring crops (1,548 lb/a) (Figure
4). Winter stand loss was estimated at 60% for winter pea and 70% for hairy vetch.
Winter lentil showed no signs of winter injury. Winter survival of winter pea and
hairy vetch was greater when grown in mixture with winter triticale than in monoculture. Treatments with winter triticale yielded the most, and there were no differences
between that set of treatments. Winter triticale treatments yielded between 4,589 and
5,174 lb/a. Treatments with spring triticale yielded the second most, ranging from
1,689 to 2,435 lb/a. Spring triticale (1,772 lb/a) did not yield any more than spring pea
(1,398 lb/a). Winter pea, hairy vetch, winter lentil, and spring lentil yielded the least.
2011 was an abnormal year. The fall of 2011 was extremely dry, and winter treatments
had to be reseeded due to very dry soil conditions at planting. Only 6.77 in. of precipitation occurred between October 1, 2010, and July 1, 2011. Of this, only 2.15 in. of
precipitation occurred between October 1, 2010, and April 1, 2011. The dry conditions and lack of fall and winter precipitation favored spring crops more than winter
crops. Spring crops (968 lb/a) yielded more than winter crops (501 lb/a; Figure 5). The
combination of dry soil conditions and winter-kill resulted in no harvestable yield of
winter lentil, hairy vetch, and winter pea. Winter survival of winter pea and hairy vetch
was greater grown in mixture with winter triticale than in monoculture. Spring triticale (1,407 lb/a), spring pea (1,264 lb/a), spring lentil/triticale (1,091 lb/a), and hairy
vetch/triticale (1,011 lb/a) yielded the most. Spring lentil yielded the least amount of
harvestable yield (174 lb/a). Spring pea/triticale, winter lentil/triticale, winter triticale,
and winter pea/triticale yielded less than spring triticale.
Averaged over years from 2008 through 2011 (2007 excluded because it was the initial
year of the study), winter triticale treatments yielded the most and spring triticale
treatments yielded the second most. Spring triticale yields were similar to spring pea/
triticale and spring pea, but spring pea/triticale yielded more than spring pea, indicating
the addition of spring pea to spring triticale tended to increase yield. Winter pea, spring
lentil, hairy vetch, and winter lentil yielded the least. Winter triticale averaged 3,675
lb/a, and spring triticale averaged 1,869 lb/a.
Conclusions
Forage yield varied based on growing season conditions, primarily precipitation and
winter injury. Winter peas and hairy vetch had significant winter injury and stand
loss. Winter lentil survived the winter well but had low yield potential and did not
add to the yield potential of winter triticale. Winter legumes had less winter injury
when grown in combination with triticale, and occasionally winter pea or hairy vetch
increased the yield potential of winter triticale; however, the additional seed cost and
risk of winter injury make planting winter pea or hairy vetch with winter triticale unadvisable. Winter triticale survived the winter well every year and yielded the most except
in 2011, which had a very dry fall and winter.
Spring triticale treatments and spring peas yielded the second most. Spring peas grown
in combination with spring triticale tended to increase the yield of spring triticale,
whereas spring lentil grown in combination with spring triticale did not improve yield.
Spring triticale averaged slightly more yield (439 lb/a) than spring pea. Spring and
14
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Cropping and Tillage Systems
winter lentil did not produce enough biomass for forage but may be grown as a cover
crop where biomass production is not a primary concern.
Table 1. Crop treatments
Season
Winter
Crop
Yellow sweet clover
Yellow sweet clover/winter triticale
Hairy vetch
Hairy vetch/winter triticale
Winter lentil
Winter lentil/winter triticale
Winter pea
Winter pea/winter triticale
Winter triticale
Winter pea (grain)
Spring lentil
Spring lentil/spring triticale
Spring pea
Spring pea/spring triticale
Spring triticale
Spring pea (grain)
Chem-fallow
Continuous winter wheat
Spring
4,000
3758a 3716a 3675a
3595a
3,500
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
3378a
2336z
2,500
2004b
1869bc
1627bc
2,000
1,500
1493y
1430c
1,000
555d 460d
391d
500
269d
tic
lov
ale
er
/tr
er
len itica
le
Sp
t
rin il/tri
t
gp
ica
ea
le
/tr
iti
Sp
ca
ri
Sp
le
rin ng t
rit
gl
ica
en
le
til
/tr
iti
ca
Sp
l
rin e
gp
ea
W
int
er
p
Sp
rin ea
gl
en
Ha
til
iry
ve
W
int tch
er
W
len
int
til
er
Sp aver
a
rin
g a ge
ve
ra
ge
ca
tri
iti
er
W
sw
llo
w
Ye
int
tc
ee
W
int
/tr
tic
tri
tch
a/
ve
pe
iry
Ha
er
le
0
int
W
x
2011
3,000
ale
Biomass dry matter yield, lb/a
Other
2007
x
Year produced
2008 2009 2010
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
Cover crop
Figure 1. Crop biomass yield, 2008–2011. Means or bars with the same lowercase letter
are not statistically different at P = 0.05.
15
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has been archived. Current information is available from http://www.ksre.ksu.edu.
4,500
4,000
3,500
3,000
2,500
2,000
1,500
1,000
500
0
3911a
3700a 3595a
3249ab
2700bc
2511bc
2712z
2327cd
2030z
1603de
877e
847e
/tr
iti
ca
w
p
le
e
sw
a
/tr
ee
iti
tc
ca
lov
le
er
/tr
iti
W
ca
int
le
er
tri
tic
Sp
ale
rin
gt
Sp
rit
rin
ica
gp
le
ea
Sp
/tr
rin
iti
gl
ca
en
le
til
/tr
iti
ca
le
Sp
rin
gp
ea
Ha
iry
ve
tch
W
int
er
pe
Sp
a
rin
gl
W
en
int
til
er
av
er
Sp
ag
rin
e
ga
ve
ra
ge
939e
er
llo
W
int
Ha
iry
ve
tch
Biomass dry matter yield, lb/a
Cropping and Tillage Systems
Ye
Cover crop
6,000
5220a
5,000
4726ab
4,000
3,000
2708z
1815d
2,000
1482d 1467d
533e
268e
0
int
W
iry
Ha
W
int
er
tri
ica
tri
t
ea
/
367e
tic
ve
ale
tch
/
t
r
er
len itica
le
til
Sp
/tr
rin
iti
gp
ca
le
ea
/tr
iti
Sp
ca
rin
le
gt
rit
ica
le
Sp
Sp
rin
rin
gp
gl
en
ea
til
/tr
iti
ca
le
W
int
er
pe
Sp
a
rin
gl
en
W
til
int
er
len
til
Ha
iry
ve
W
int
tch
er
av
er
Sp
ag
rin
e
ga
ve
ra
ge
0
er
p
1296y
1266d
1,000
int
W
4503b
3703c
le
Biomass dry matter yield, lb/a
Figure 2. Crop biomass yield, 2008. Means or bars with the same lowercase letter are not
statistically different at P = 0.05.
Cover crop
Figure 3. Crop biomass yield, 2009. Means or bars with the same lowercase letter are not
statistically different at P = 0.05.
16
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has been archived. Current information is available from http://www.ksre.ksu.edu.
6,000
5174a
5,000
4932a 4763a
4589a
4,000
3018z
3,000
2435b
1772bc 1689bc
2,000
1548y
1398cd
1,000
671de 527e
472e
447e
0
W
int
W
int
er
tr
er
len itica
le
til
Ha
/tr
iry
i
t
ica
ve
tch
le
W
/tr
int
i
tic
er
ale
pe
a/
Sp
t
rin
rit
ica
gp
le
ea
/tr
iti
Sp
ca
rin
le
Sp
gt
rin
rit
gl
ica
en
le
til
/tr
iti
ca
le
Sp
rin
gp
ea
W
int
er
pe
Ha
a
iry
ve
tch
W
int
er
len
Sp
til
rin
g
W
len
int
til
er
av
er
Sp
ag
rin
e
ga
ve
ra
ge
Biomass dry matter yield, lb/a
Cropping and Tillage Systems
Cover crop
1,600
1,400
1407a
1264ab
1,200
1091abc
1011abc
1,000
800
902bc 872bc
846c
968z
780c
600
501y
400
174d
200
0d
0d
gp
Ha
ing
Sp
r
iry
rin
ica
Sp
tri
t
ing
Sp
r
0d
len
ea
til
/tr
iti
ve
ca
t
le
c
Sp
h/
t
rin
rit
gp
ica
le
W
ea
int
/tr
er
iti
ca
len
le
til
/tr
iti
W
ca
int
le
er
W
int
tri
tic
er
ale
pe
a/
tri
tic
ale
Sp
rin
gl
en
W
til
int
er
len
til
Ha
iry
ve
tch
W
int
er
W
pe
int
a
er
av
er
Sp
ag
rin
e
ga
ve
ra
ge
0
le
Biomass dry matter yield, lb/a
Figure 4. Crop biomass yield, 2010. Means or bars with the same lowercase letter are not
statistically different at P = 0.05.
Cover crop
Figure 5. Crop biomass yield, 2011. Means or bars with the same lowercase letter are not
statistically different at P = 0.05.
17
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Cropping and Tillage Systems
Effect of Simulated Hail Damage on Corn Yield
J. Holman, T. Roberts, S. Maxwell, and M. Zarnstorff
Summary
Hail damage is a common occurrence throughout Kansas. This study evaluated the
impact of simulated hail damage (stand thinning) on corn at at V5, V8, V11, and V14
growth stages in 2008, 2009, and 2010. The amount that the stand was thinned had a
greater impact on corn yield components, yield, and grain quality than the crop stage at
thinning. Plants thinned early tended to yield slightly more than plants thinned later.
In part, this was because they were able to produce more kernels per ear than plants
thinned at V14. Crop yield was reduced at each additional level of thinning. Corn yield
was able to partly compensate for thinning by increasing kernel weight, kernels per ear,
and ears per plant. Thinning reduced test weight and increased protein content.
Introduction
Hailstorms are a common cause of crop damage in Kansas. Diagnosing and determining
the amount of crop injury is important in determining yield loss.
Hail damage always makes corn look bad, and can make for some sleepless nights.
Although the physical damage is apparent, the actual effect on yield is not as obvious. Potential corn yield losses from hail gradually increase as the crop matures, up to
the silk stage, when peak yield loss occurs. After silking, yield losses from hail damage
normally decline again.
From emergence through stem elongation (VE to V5)
Through the five-leaf stage of growth, the growing point of corn is below the soil
surface. Hail damage could remove all five leaves but not damage the growing point.
A corn plant has 24 to 26 leaves at tasseling; even if the plant loses five of those leaves
early on, it will still have the potential to have 19 to 21 leaves at tasseling. Yield will be
reduced, but by much less than one might expect from the appearance of the plant.
From stem elongation to tassel (V6 to VT)
The growing point begins extending aboveground by the 6-leaf stage, although it is still
protected by several layers of leaves and sheaths. The number of rows that will be in the
ear is established by the 12-leaf stage. Stress during V8 to V11 can reduce row number.
The number of kernels per row is not determined until about V17, just before tasseling. Hail damage and loss of leaf area during these stages of growth can increase the
potential for yield loss. Hail can also cause stalk bruising during these stages of growth,
but determining the amount of damage from stalk bruising is difficult until later in the
season.
From tassel to maturity (VT to R6)
At VT to R1 (tassel to silk), the corn plant is more vulnerable to hail damage than at
any other stage because the tassel and all leaves are exposed. No more leaves will be
developed, and the plant cannot replace a damaged tassel. Furthermore, the stalk is
exposed, with only one layer of leaf sheath protecting it. Unlike wheat, corn cannot fill
18
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Cropping and Tillage Systems
from the stem if leaves are lost at this stage of growth. The six to eight leaves above the
ear are the most important, and provide most of the grain fill.
The four-week period surrounding silking is critical to corn, and not only in regard to
hail damage. Drought stress, excessive moisture, extreme heat, diseases, and high winds
can all stress the plant and reduce yields at this stage of growth. Early in this period,
stress can reduce kernel number by limiting potential ear size. Stress right at silking can
reduce the number of kernels fertilized, and stress just after silking can cause fertilized
kernels to abort.
Procedures
Corn was planted at 36,000 plants/a and thinned to 34,000 plants/a after all corn
emerged. Corn was fully irrigated using an overhead pivot. Corn stands were thinned
randomly by hand-thinning 0%, 25%, 50%, and 75% at V5, V8, V11, and V14, respectively. Plots were 4 rows wide on 30-in. centers and 30 ft long. Final plant stand, ears
per plant, kernels per ear, yield, test weight, 1,000 kernel weight, and protein content
were measured from the center 2 rows the full length of the plot. Plots were harvested
with a plot combine at grain maturity. Grain yield was adjusted to 15.5% moisture
content and test weight was measured using a grain analysis computer. Grain samples
were analyzed for nitrogen and converted to protein content. This study was conducted
in 2008, 2009, and 2011. For the purposes of this report, results from all years were
shown.
Results and Discussion
Yield (bu/a)
Corn yield varied by year (P ≤ 0.01). Thinning at earlier crop stages tended to yield
more than later thinning (P = 0.08) (Figure 1). Yield was reduced as the amount of
thinning increased (P ≤ 0.01). Yields averaged 183 bu/a with 0% thinning, 165 bu/a
with 25% thinning, 137 bu/a with 50% thinning, and 78 bu/a with 75% thinning.
Kernel weight (g/1,000 kernels)
Kernel weight varied by year (P ≤ 0.01). Crop stage did not affect kernel weight. Stands
thinned 50 and 75% had greater kernel weight (309 g/1,000 kernels) than stands
thinned 0 or 25% (295 g/1,000 kernels) (P ≤ 0.01) (Figure 2).
Kernels per ear
Kernels produced per ear varied by year (P ≤ 0.01). More kernels were produced per
ear when plants were thinned at V5, V8, or V11 (407 kernels/ear) compared with V14
(564 kernels/ear) (P ≤ 0.01) (Figure 3). No differences were observed in crop stage
from V5 to V11. Stands thinned 50 and 75% had more kernels per ear (671 kernels/
ear) than stands thinned 25% (566 kernels/ear) or 0% (498 kernels/ear) (P ≤ 0.01).
Stands thinned 25% had more kernels per ear than stands thinned 0%.
Ears per plant
The number of ears produced per plant was not affected by year or crop stage. Stands
thinned 75% had more ears per plant (1.11 ears/plant) than the other thinning levels
(0.99 ears/plant) (P ≤ 0.01) (Figure 4).
19
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Cropping and Tillage Systems
Test weight (lb/bu)
Test weight varied by year (P ≤ 0.01). Crop stage did not affect test weight. Stands
thinned 50 and 75% had lower test weights (58.9 lb/bu) than stands thinned 0 or 25%
(59.4 lb/bu) (P ≤ 0.01) (Figure 5).
Protein
Protein content of the grain varied by year (P ≤ 0.01). Crop stage did not affect protein
content. Stands thinned 75% had more protein (8.6%) than the other thinning levels
(8.1%) (P ≤ 0.01) (Figure 6).
Conclusions
The amount that the stand was thinned had a greater impact on corn yield components,
yield, and grain quality than the crop stage at thinning. Although not significant, plants
thinned early tended to yield more than plants thinned later. In part, this was because
plants thinned early were able to produce more kernels per ear than plants thinned at
V14. Crop yield was reduced at each additional level of thinning, but corn yield was
able to partly compensate for thinning by increasing kernel weight, kernels per ear, and
ears per plant. Thinning reduced test weight and increased protein content.
This study found slightly different results than research conducted by Dr. Barney
Gordon at the North Central Kansas Experiment Field. In that study, yield was affected
more by the crop stage thinning that occurred, and thinning affected seed weight; in
this study, thinning increased seed weight. In both studies, percentage yield loss was less
than the percentage of the stand thinned at every growth stage.
When considering replanting due to poor stands or early season hail damage, keep in
mind that planting corn in early June, in much of Kansas, can result in yield losses of up
to 50% compared to a typical planting date. Based on the above data, retaining an existing stand even with as much as 50% stand loss would probably be better than replanting
in early June. Much depends, of course, on the uniformity of the remaining stand and
the weather for the rest of the growing season.
20
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Cropping and Tillage Systems
200
180
140
120
100
80
60
0
40
25
20
0
V5
Thinning, %
Corn yield, bu/a
160
50
V8
V11
Plant growth stage
75
V14
Figure 1. Corn yield response to percentage of stand thinned (0, 25, 50, and 75%) at V5,
V8, V11, and V14.
315
310"
305
300
295
290
75
285
50
280
275
V5
25
V8
V11
Plant growth stage
0
Thinning, %
Kernel weight, g/1,000 kernels
320
V14
Figure 2. Kernel weight response to percentage of stand thinned (0, 25, 50, and 75%) at
V5, V8, V11, and V14.
21
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has been archived. Current information is available from http://www.ksre.ksu.edu.
Cropping and Tillage Systems
800
700
500
400
300
200
75
100
50
0
V5
Thinning, %
Kernels per ear
600
25
V8
V11
Plant growth stage
0
V14
Figure 3. Kernels per ear response to percentage of stand thinned (0, 25, 50, and 75%) at
V5, V8, V11, and V14.
1.20
0.80
0.60
0.40
75
0.20
50
0
V5
25
V8
V11
Plant growth stage
0
V14
Figure 4. Ears per plant response to percentage of stand thinned (0, 25, 50, and 75%) at
V5, V8, V11, and V14.
22
Thinning, %
Ears per plant
1.00
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Cropping and Tillage Systems
59.80
59.60
59.20
59.00
58.80
58.60
0
58.40
25
58.20
58.00
V5
50
V8
V11
Plant growth stage
75
Thinning, %
Test weight, lb/bu
59.40
V14
Figure 5. Test weight response to percentage of stand thinned (0, 25, 50, and 75%) at V5,
V8, V11, and V14.
9.2
9.0
8.6
8.4
8.2
8.0
75
7.8
50
7.6
7.4
V5
25
V8
V11
Plant growth stage
0
Thinning, %
Grain protein, %
8.8
V14
Figure 6. Protein response to percentage of stand thinned (0, 25, 50, and 75%) at V5, V8,
V11, and V14.
23
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Cropping and Tillage Systems
Fallow Replacement Crop Effects on
Wheat Yield
J. Holman, T. Dumler, T. Roberts, and S. Maxwell
Summary
Producers are interested in growing cover crops and reducing fallow. A study was initiated in 2007 to evaluate several crops grown in place of fallow in a no-till wheat-fallow
system. Wheat yields following cover crops and annual forages were similar to yields
following chemical fallow when the cover crop or annual forage crop was terminated
from May 15 through June 1, with the exception of winter triticale. Winter triticale
reduced wheat yield about 5 bu/a compared with fallow. Cover crops did not increase
wheat yields. Wheat yielded less when grown continuously or after grain peas compared
with fallow. The fallow period can be shortened without reducing wheat yield. Grain
peas and annual forages provide an economic return, whereas cover crops are an expense
to grow.
Introduction
Interest in growing cover crops and replacing fallow with a cash crop has necessitated
research on wheat yields following a shortened fallow period. Fallow stores moisture,
which helps stabilize crop yields and reduce the risk of crop failure; however, only 25
to 30% of the precipitation received during the fallow period of a no-till, wheat-fallow
rotation is stored. The remaining 70 to 85% precipitation is lost primarily to evaporation. Moisture storage in fallow is more efficient earlier in the fallow period when the
soil is dry and during the winter months when the evaporation rate is lower. Increasing
cropping intensity without reducing winter wheat yield may be possible. This study
evaluated the effects of replacing part of the fallow period with a cover, annual forage,
or short-season grain crop on the following winter wheat yield.
Procedures
Fallow replacement crops (cover, annual forage, or short-season grain crops) have been
grown during the fallow period of a no-till, wheat-fallow cropping system every year
since 2007. Crops were grown as cover, harvested for forage (annual forage crop), or
harvested for grain. Both winter and spring crop species were evaluated. Winter species
included yellow sweet clover (Melilotus officinalis (L.) Lam.), hairy vetch (Vicia villosa
Roth ssp.), lentil (Lens culinaris Medik.), Austrian winter forage pea (Pisum sativum
L. ssp.), Austrian winter grain pea (Pisum sativum L. ssp.), and triticale (×Triticosecale Wittm.). Spring species included lentil (Lens culinaris Medik.), forage pea (Pisum
sativum L. ssp.), grain pea (Pisum sativum L. ssp.), and triticale (×Triticosecale Wittm.)
Crops were grown in monoculture and in two-species mixtures of each legume plus
triticale. Crops grown for grain were grown only in monoculture. Winter lentil was
grown in place of yellow sweet clover beginning in 2009. Crops grown in place of fallow
were compared with a wheat-fallow and continuous wheat rotation for a total of
16 treatments (Table 1.) The study design was a split-split-plot randomized complete
block design with 4 replications; crop phase was the main plot, crop species was the
split-plot, and termination method (forage, grain, or cover) was the split-split-plot.
24
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Cropping and Tillage Systems
Winter crops were planted approximately October 1. Winter cover and forage crops
were terminated or harvested approximately May 15. Spring crops were planted from
the end of February through the middle of March. Spring cover and forage crops were
terminated or harvested approximately June 1. Winter and spring grain peas were
harvested with a small plot combine at grain maturity, which was approximately July 1.
Volumetric soil moisture content was measured at cover crop termination and winter
wheat planting using a Giddings Soil Probe (Giddings Machine Company, Windsor,
CO) to a 6-ft soil depth. Grain yield was adjusted to 13.5% moisture content, and test
weight was measured using a grain analysis computer. Grain samples were analyzed for
nitrogen content.
Results and Discussion
Winter wheat yield
In 2008, hail damaged the wheat crop 1 week before harvest; therefore, no statistical
separation was made between treatments. Winter wheat yield following a fallow crop
ranged from 21 to 26 bu/a, wheat yield following wheat was 13 bu/a, and wheat yield
following fallow was 22 bu/a (Figure 1).
In 2009, grain pea and winter clover/triticale yielded 7 and 9 bu/a less than fallow
(83 bu/a), and spring pea yielded 7 bu/a more than fallow (Figure 2). Continuous
wheat yielded least of all (57 bu/a). All other treatments yielded similar to fallow.
In 2010, winter pea/triticale and winter triticale yielded 5 and 7 bu/a less than fallow
(70 bu/a), and spring lentil/triticale and spring pea/triticale yielded 4 and 6 bu/a less
than fallow (Figure 3). Continuous wheat yielded least of all (43 bu/a). All other treatments had yields similar to fallow. Wheat following cover crops yielded an average of
2.9 bu/a more than wheat following a hay crop.
In 2011, only 6.77 in. of precipitation occurred between October 1, 2010, and July 1,
2011. This drought resulted in low wheat yields and a greater impact of the preceding crop on wheat yield. Wheat grown following a winter cover or forage crop yielded
less than fallow with the exception of winter lentil (22 bu/a), which yielded similar to
fallow (23 bu/a) (Figure 4). Wheat yield following all other winter crops was reduced
by 4 to 10 bu/a. Wheat yield following spring cover or forage crops was not affected as
much as winter crops. Wheat yield following spring lentil, triticale, and lentil/triticale
was similar to fallow and wheat following spring pea and pea/triticale was reduced
7 and 3 bu/a, respectively. Wheat following grain pea was reduced 11 bu/a, and wheat
following wheat was reduced 16 bu/a compared with fallow.
Wheat harvested in 2012 will be the final wheat yield collected from a wheat-fallow
rotation. Future research will evaluate replacing fallow in a wheat-grain sorghum-fallow
rotation.
Averaged over years from 2009 through 2011 (2008 excluded due to hail damage),
there was no difference whether the previous crop was grown as forage or cover
(P = 0.09). Winter crops with triticale yielded 4 to 7 bu/a less than fallow, winter
legume monocultures yielded similar to fallow, and all spring crops yielded similar to
25
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Cropping and Tillage Systems
fallow (Figure 5). Grain peas yielded 7 bu/a less, and continuous wheat yielded 23 bu/a
less than fallow.
Cover vs. annual forage
Across years (2009–2011), whether the previous crop was left as cover or harvested
for forage did not affect wheat yield. In 2010, wheat following cover crops yielded an
average of 2.9 bu/a more than wheat following a hay crop. This result indicates that
the previous crop can be harvested for forage without negatively affecting wheat yield
compared with growing a cover crop.
Conclusions
This study found the cropping system can be intensified by replacing part of the fallow
period with annual forages or cover crops without reducing the following wheat yield.
Winter triticale, continuous wheat, and grain peas reduced wheat yield, but all other
treatments yielded similar to fallow. The reduced wheat yield following these treatments was likely due to less available soil moisture at wheat planting. Cover crops did
not improve wheat yield. Forages provide an economic return, but cover crops are an
expense to grow. A detailed economic analysis is needed; preliminary analysis suggests
annual forages and grain peas increase returns whereas continuous winter wheat and
cover crops reduce returns.
Table 1. Crop treatments
Season
Winter
Spring
Other
26
Crop
Yellow sweet clover
Yellow sweet clover/winter triticale
Hairy vetch
Hairy vetch/winter triticale
Winter lentil
Winter lentil/winter triticale
Winter pea
Winter pea/winter triticale
Winter triticale
Winter pea (grain)
Spring lentil
Spring lentil/spring triticale
Spring pea
Spring pea/spring triticale
Spring triticale
Spring pea (grain)
Chem-fallow
Continuous winter wheat
2007
x
x
x
x
x
x
x
x
Year produced
2008 2009 2010
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
2011
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
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has been archived. Current information is available from http://www.ksre.ksu.edu.
23
24
at
tc
lov
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sw
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ee
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/tr
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nt
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0
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he
Winter wheat yield, bu/a 13.5%
Cropping and Tillage Systems
None
100
90
80
70
60
50
40
30
20
10
0
74g
81dcef
77efg 78efg
76fg
86abc 87abc
79defg
83bcde 85abcd
89ab
90a
83bcde
Winter
llo
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nt
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iti
/tr
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iti
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tch
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tch
/tr
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gr
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r/t
rit
ica
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57h
at
Winter wheat yield, bu/a 13.5%
Figure 1. 2008 winter wheat yield following 2007 cover crops. No mean separation
performed.
Spring
None
Figure 2. 2009 winter wheat yield following 2008 cover crops. Means or bars with the same
lowercase letter are not statistically different at P = 0.05.
27
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
80
70
68bcd 70ab
65cde 66bcde 66bcde
63e
72a
70ab
67bcde 67bcde 68abc
64de 66cde
70ab
60
50
43f
40
30
20
10
Pe
a
Tr
iti
ca
le
Le
nt
il
Fa
llo
w
Ha
til
iry
ve
tch
Pe
a/
t
r
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iti
ca
nt
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ile
/tr
iti
ca
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n
Pe
W
he
a
0
at
Tr
iti
ca
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le
a/
tri
tic
ale
Pe
Ha
a(
iry
gr
ve
tch ain)
/tr
Le
iti
ca
nt
ile
le
/tr
iti
ca
le
Winter wheat yield, bu/a 13.5%
Cropping and Tillage Systems
Winter
Spring
None
30
25a
25
22bc
20
16ef 17ef 17def
15
20cd
18def 19de
10
25a
22bc
23ab
16fg
13gh
12h
7i
5
le
nt
il
Fa
llo
w
Le
ca
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iti
ale
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nt
il/
tri
tic
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in)
gr
a
nt
il
Pe
a(
Le
ca
le
le
iti
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tic
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il/
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/tr
iti
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iry
ve
tch
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a
iry
Ha
ca
iti
/tr
he
Pe
a
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le
0
at
Winter wheat yield, bu/a 13.5%
Figure 3. 2010 winter wheat yield following 2009 cover crops. Means or bars with the same
lowercase letter are not statistically different at P = 0.05.
Winter
Spring
None
Figure 4. 2011 winter wheat yield following 2010 cover crops. Means or bars with the same
lowercase letter are not statistically different at P = 0.05.
28
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
70
60
55ef
56ef
57ef 58def
61abcd
64ab
65a
61abcd 62abc
59cde 60bcd
64ab
62abc
55f
50
40
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30
20
10
Spring
a
Tr
iti
ca
le
Le
nt
il
Gr
ain
pe
a
Fa
llo
w
Pe
til
a/
tri
t
Le
ica
nt
le
il/
tri
tic
ale
Le
n
Pe
W
he
Pe
Winter
Pe
Ha
a
iry
ve
tch
0
at
a/
tri
tic
ale
Tr
iti
Le
ca
n
le
til
Ha
/tr
iry
i
tic
ve
ale
tch
/tr
iti
ca
le
Winter wheat yield, bu/a 13.5%
Cropping and Tillage Systems
Winter
and
spring
None
Figure 5. 2009–2011 winter wheat yield following cover crops. Means or bars with the
same lowercase letter are not statistically different at P = 0.05.
29
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Cropping and Tillage Systems
Four-Year Rotations with Wheat and
Grain Sorghum
A. Schlegel, T. Dumler, J. Holman, and C. Thompson
Summary
Research on four-year crop rotations with wheat and grain sorghum was initiated at
the Southwest Research-Extension Center near Tribune, KS, in 1996. Rotations were
wheat-wheat-sorghum-fallow (WWSF), wheat-sorghum-sorghum-fallow (WSSF),
and continuous wheat (WW). Soil water at wheat planting following sorghum averaged about 9 in., which is about 3 in. more than the second wheat crop in a WWSF
rotation. Soil water at sorghum planting was approximately 1.5 in. less for the second
sorghum crop, compared with sorghum following wheat. Grain yield of recrop wheat
averaged about 80% of the yield of wheat following sorghum. Grain yield of continuous
wheat averaged about 65% of the yield of wheat grown in a four-year rotation following sorghum. Wheat yields were similar following one or two sorghum crops. Similarly,
average sorghum yields were the same following one or two wheat crops. Yield of the
second sorghum crop in a WSSF rotation averaged 65% of the yield of the first sorghum
crop.
Introduction
In recent years, cropping intensity has increased in dryland systems in western Kansas.
The traditional wheat-fallow system is being replaced by wheat-summer crop-fallow
rotations. With concurrent increases in no-till, is more intensive cropping feasible?
Objectives of this research were to quantify soil water storage, crop water use, and crop
productivity of four-year and continuous cropping systems.
Procedures
Research on four-year crop rotations with wheat and grain sorghum was initiated at
the Tribune Unit of the Southwest Research-Extension Center in 1996. Rotations
were WWSF, WSSF, and WW. No-till was used for all rotations. Available water was
measured in the soil profile (0 to 8 ft) at planting and harvest of each crop. The center of
each plot was machine harvested after physiological maturity, and yields were adjusted
to 12.5% moisture.
Results and Discussion
Soil water
The amount of available water in the soil profile (0 to 6 ft) at wheat planting varied
greatly from year to year (Figure 1). Soil water was similar following fallow after either
one or two sorghum crops, and averaged about 9 in. across the 15-year study period.
Water at planting of the second wheat crop in a WWSF rotation generally was less
than that at planting of the first wheat crop, except in 1997 and 2003. Soil water for the
second wheat crop averaged more than 3 in. (or about 40%) less than that for the first
wheat crop in the rotation. Continuous wheat averaged about 0.7 in. less water at planting than the second wheat crop in a WWSF rotation.
30
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Cropping and Tillage Systems
Similar to wheat, the amount of available water in the soil profile at sorghum planting varied greatly from year to year (Figure 2.) Soil water was similar following fallow
after either one or two wheat crops and averaged about 8.25 in. over 16 years. Water at
planting of the second sorghum crop in a WSSF rotation was generally less than that
at planting of the first sorghum crop. Averaged across the entire study period, the first
sorghum crop had about 1.5 in. more available water at planting than the second crop.
Grain yields
In 2011, wheat yields were below average because of a dry fall and winter (Table 1).
Averaged across 15 years, recrop wheat (the second wheat crop in a WWSF rotation)
yielded about 80% of the yield of first-year wheat in WWSF. Before 2003, recrop wheat
yielded about 70% of the yield of first-year wheat. In 2003 and 2009, however, recrop
wheat yields were much greater than the yield in all other rotations. For 2003 recrop
wheat, this is possibly a result of failure of the first-year wheat in 2002, which resulted
in a period from 2000 sorghum harvest to 2003 wheat planting without a harvested
crop; however, this was not the case for the 2009 recrop wheat. Generally, little difference has occurred in wheat yields following one or two sorghum crops. In most years,
continuous wheat yields have been similar to recrop wheat yields, but in several years
(2003, 2007, and 2009), recrop wheat yields were considerably greater than continuous
wheat yields.
Sorghum yields in 2011 were greater than average for sorghum following wheat, but
average for sorghum following sorghum (Table 2). Sorghum yields were similar following one or two wheat crops, which is consistent with the long-term average. The second
sorghum crop typically averages about 65% of the yield of the first sorghum crop, but in
2010, recrop sorghum yields were less than 50% of the yield of the first sorghum crop.
31
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32
Table 1. Wheat response to rotation, Tribune, 1997–2011
Rotation
1
1
W, wheat; S, sorghum; F, fallow; capital letters denote current year’s crop.
Table 2. Grain sorghum response to rotation, Tribune, 1996–2011
Rotation
1
wSsf
wsSf
wwSf
LSD (0.05)
1
Grain sorghum yield
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 Mean
---------------------------------------------------------------------------------------------- bu/a ---------------------------------------------------------------------------------------------58
88
117
99
63
68
0
60
91
81
55
101
50
89
98
119
77
35
45
100
74
23
66
0
41
79
69
13
86
30
44
52
47
50
54
80
109
90
67
73
0
76
82
85
71
101
57
103
105
105
79
24
13
12
11
16
18
—
18
17
20
15
9
12
53
24
34
4
W, wheat; S, sorghum; F, fallow; capital letters denote current year’s crop.
Cropping and Tillage Systems
Wssf
Wwsf
wWsf
WW
LSD (0.05)
Wheat yield
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
Mean
---------------------------------------------------------------------------------------------- bu/a ---------------------------------------------------------------------------------------------57
70
74
46
22
0
29
6
45
28
75
40
37
63
25
41
55
64
80
35
29
0
27
6
40
26
61
40
39
60
22
39
48
63
41
18
27
0
66
1
41
7
63
5
50
29
25
32
43
60
43
18
34
0
30
1
44
2
41
6
24
23
17
26
8
12
14
10
14
—
14
2
10
8
14
5
15
9
8
2
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Cropping and Tillage Systems
Wssf
Wwsf
wWsf
WW
Available water, in.
12
10
8
6
4
2
0
1997
1999
2001
2003
2005
Year
2007
2009
2011
Figure 1. Available soil water at planting of wheat in several rotations, Tribune,
1997–2011.
Capital letter denotes current crop in rotation (W, wheat; S, sorghum; F, fallow). The last set of
bars (Mean) is the average across years.
wwSf
wSsf
wsSf
14
Available water, in.
12
10
8
6
4
2
0
1996
1999
2002
2005
2008
2011
Year
Figure 2. Available soil water at planting of sorghum in several rotations, Tribune,
1996–2011.
Capital letter denotes current crop in rotation (W, wheat; S, sorghum; F, fallow). The last set of
bars (Mean) is the average across years.
33
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Soil Fertility
Nitrogen and Phosphorus Fertilization
of Irrigated Corn
A. Schlegel
Summary
Long-term research shows that phosphorus (P) and nitrogen (N) fertilizer must be
applied to optimize production of irrigated corn in western Kansas. In 2011, N applied
alone increased yields 87 bu/a, whereas P applied alone increased yields 13–19 bu/a.
N and P applied together increased yields up to 139 bu/a. This is similar to the past 10
years, where N and P fertilization increased corn yields up to 130 bu/a. Application of
120 lb/a N (with P) was sufficient to produce about 95% of maximum yield in 2011,
which was similar to the 10-year average. Application of 80 instead of 40 lb P2O5/a
increased average yields of only 2 bu/a in 2011. Soil organic matter was increased by N
and P fertilization. Soil pH was decreased by increased N rates and not affected by P
fertilization. Application of 40 lb P2O5/a was not sufficient to maintain soil test P levels.
Introduction
This study was initiated in 1961 to determine responses of continuous corn and grain
sorghum grown under flood irrigation to N, P, and potassium (K) fertilization. The
study is conducted on a Ulysses silt loam soil with an inherently high K content. No
yield benefit to corn from K fertilization was observed in 30 years, and soil K levels
remained high, so the K treatment was discontinued in 1992 and replaced with a higher
P rate.
Procedures
This field study is conducted at the Tribune Unit of the Southwest Research-Extension
Center. Fertilizer treatments initiated in 1961 are N rates of 0, 40, 80, 120, 160, and
200 lb/a without P and K; with 40 lb/a P2O5 and zero K; and with 40 lb/a P2O5 and 40
lb/a K2O. The treatments were changed in 1992, when the K variable was replaced by a
higher rate of P (80 lb/a P2O5). All fertilizers were broadcast by hand in the spring and
incorporated before planting. The soil is a Ulysses silt loam. The corn hybrids [Pioneer
33R93 (2002), DeKalb C60-12 (2003), Pioneer 34N45 (2004 and 2005), Pioneer
34N50 (2006), Pioneer 33B54 (2007), Pioneer 34B99 (2008), DeKalb 61-69 (2009),
Pioneer 1173H (2010), and Pioneer 1151XR (2011)] were planted at about 30,000
to 32,000 seeds/a in late April or early May. Hail damaged the 2002, 2005, and 2010
crops. The corn is irrigated to minimize water stress; sprinkler irrigation has been used
since 2001. The center two rows of each plot are machine harvested after physiological
maturity. Grain yields are adjusted to 15.5% moisture. Soil samples (0–6 in.) were taken
following harvest in 2010. Soil test P was determined by two methods; Bray-1 because
the historical analyses used this method, and Olsen because of the high pH in some
treatments.
Results
Corn yields in 2011 were much greater than the 10-year average (Table 1). Nitrogen
alone increased yields 87 bu/a, whereas P alone increased yields less than 20 bu/a;
34
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Soil Fertility
however, N and P applied together increased corn yields up to 139 bu/a. Only 120 lb/a
N with P was required to obtain 95% of maximum yield, which is similar to the 10-year
average. Corn yields in 2011 (averaged across all N rates) were only 2 bu/a greater with
80 than with 40 lb/a P2O5, which is slightly less than the 10-year average of 5 bu/a.
Soil organic matter was increased by N and P fertilization of corn from 2.1% in the
non-fertilized control to a maximum of 2.5% with 200 lb/a of N with P (Table 2). Soil
test P averaged across N rates was higher with 40 lb/a P2O5 than without P (15 vs. 8 ppm
Bray-1 P), but still slightly less than at the start of the study (17 ppm Bray-1 P in 1961).
Application of 80 lb/a P2O5 since 1992 to corn resulted in a buildup of soil test P to
26 ppm by 2010. Soil test P, based on the Olsen test, showed similar trends to that
using the Bray-1 P test. Long-term N applications decreased soil pH whereas P fertilization had no effect on soil pH.
35
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
36
Soil Fertility
Table 1. Effect of nitrogen and phosphorus fertilization on irrigated corn, Tribune, KS, 2002–2011
N
P2O5
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
Mean
----------- lb/a ----------------------------------------------------------------------------------------------- bu/a ------------------------------------------------------------------------------------0
0
39
79
67
49
42
49
36
85
20
92
56
0
40
43
95
97
60
68
50
57
110
21
111
71
0
80
44
93
98
51
72
51
52
106
28
105
70
40
0
47
107
92
63
56
77
62
108
23
114
75
40
40
69
147
154
101
129
112
105
148
67
195
123
40
80
76
150
148
100
123
116
104
159
61
194
123
80
0
53
122
118
75
79
107
78
123
34
136
92
80
40
81
188
209
141
162
163
129
179
85
212
155
80
80
84
186
205
147
171
167
139
181
90
220
159
120
0
50
122
103
66
68
106
65
117
28
119
84
120
40
78
194
228
162
176
194
136
202
90
222
168
120
80
85
200
234
170
202
213
151
215
105
225
180
160
0
50
127
136
83
84
132
84
139
49
157
104
160
40
80
190
231
170
180
220
150
210
95
229
176
160
80
85
197
240
172
200
227
146
223
95
226
181
200
0
67
141
162
109
115
159
99
155
65
179
125
200
40
79
197
234
169
181
224
152
207
97
218
176
200
80
95
201
239
191
204
232
157
236
104
231
189
continued
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Means
Nitrogen, lb/a
0
40
80
120
160
200
LSD (0.05)
P2O5, lb/a
0
40
80
LSD (0.05)
42
64
73
71
71
80
8
89
135
165
172
172
180
9
87
132
178
188
203
212
11
53
88
121
133
142
156
10
61
103
137
149
155
167
15
50
102
146
171
193
205
11
48
91
115
118
127
136
9
100
138
161
178
191
199
12
23
50
70
74
80
89
9
103
167
189
189
204
209
13
66
107
135
144
154
163
8
51
72
78
6
116
168
171
6
113
192
194
8
74
134
139
7
74
149
162
11
105
160
168
8
71
122
125
6
121
176
187
9
36
76
81
7
133
198
200
9
89
145
150
6
Soil Fertility
Table 1. Effect of nitrogen and phosphorus fertilization on irrigated corn, Tribune, KS, 2002–2011
N
P2O5
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
Mean
----------- lb/a ----------------------------------------------------------------------------------------------- bu/a ------------------------------------------------------------------------------------ANOVA (P > F)
Nitrogen
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
Linear
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
Quadratic
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
Phosphorus
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
Linear
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
Quadratic
0.007
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
N×P
0.133
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
37
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Soil Fertility
Table 2. Selected soil properties (0–6 in.) after long-term (50 years) applications of
nitrogen and phosphorus fertilizers to irrigated corn, Tribune, KS, 2010
N
P2O5
Soil OM
Bray 1 P
Olsen P
Soil pH
----------- lb/acre ----------%
------------ ppm -----------0
0
2.1
7
4
7.8
40
2.1
23
14
7.8
80†
2.1
25
15
7.7
40
0
2.1
8
5
7.8
40
2.4
15
9
7.7
80
2.3
27
16
7.6
80
0
2.2
7
4
7.6
40
2.3
10
6
7.6
80
2.4
23
14
7.6
120
0
2.2
8
5
7.7
40
2.4
12
7
7.6
80
2.5
23
13
7.5
160
0
2.3
8
5
7.4
40
2.4
14
7
7.2
80
2.4
23
13
7.4
200
0
2.4
8
4
6.9
40
2.5
15
8
7.2
80
2.5
34
17
7.1
continued
38
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Soil Fertility
Table 2. Selected soil properties (0–6 in.) after long-term (50 years) applications of
nitrogen and phosphorus fertilizers to irrigated corn, Tribune, KS, 2010
N
P2O5
Soil OM
Bray 1 P
Olsen P
Soil pH
----------- lb/acre ----------%
------------ ppm -----------ANOVA (P > F)
Nitrogen
0.001
0.017
0.008
0.001
Linear
0.001
0.868
0.071
0.001
Quadratic
0.279
0.001
0.001
0.007
P2O5
0.001
0.001
0.001
0.786
Linear
0.001
0.001
0.001
0.591
Quadratic
0.078
0.136
0.070
0.664
N×P
0.338
0.044
0.035
0.485
Means
Nitrogen
0
40
80
120
160
200
LSD (0.05)
P2O5
0
40
80
LSD (0.05)
2.1
2.3
2.3
2.3
2.4
2.5
0.1
19
17
13
14
15
19
4
11
10
8
8
8
10
2
7.8
7.7
7.6
7.6
7.3
7.1
0.2
2.2
2.3
2.4
0.1
8
15
26
3
4
8
15
1
7.5
7.5
7.5
0.1
† The 80 lb/a rate of P2O5 was applied starting in 1992; prior to then it was 40 lb/a.
39
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Soil Fertility
Nitrogen and Phosphorus Fertilization
of Irrigated Grain Sorghum
A. Schlegel
Summary
Long-term research shows that phosphorus (P) and nitrogen (N) fertilizer must be
applied to optimize production of irrigated grain sorghum in western Kansas. In 2011,
N applied alone increased yields about 50 bu/a, whereas N and P applied together
increased yields up to 75 bu/a. Averaged across the past 10 years, N and P fertilization
increased sorghum yields more than 60 bu/a. Application of 40 lb/a N (with P) was
sufficient to produce about 80% of maximum yield in 2011, which was slightly less than
the 10-year average. Application of potassium (K) has had no effect on sorghum yield
throughout the study period. Soil organic matter was increased by N and P fertilization.
Soil pH was decreased by increased N rates and not affected by P fertilization. Application of 40 lb P2O5/a was sufficient to maintain soil test P levels.
Introduction
This study was initiated in 1961 to determine responses of continuous grain sorghum
grown under flood irrigation to N, P, and K fertilization. The study is conducted on
a Ulysses silt loam soil with an inherently high K content. The irrigation system was
changed from flood to sprinkler in 2001.
Procedures
This field study is conducted at the Tribune Unit of the Southwest Research-Extension
Center. Fertilizer treatments initiated in 1961 are N rates of 0, 40, 80, 120, 160, and
200 lb/a N without P and K; with 40 lb/a P2O5 and zero K; and with 40 lb/a P2O5
and 40 lb/a K2O. All fertilizers are broadcast by hand in the spring and incorporated
before planting. Sorghum (Pioneer 8500/8505 from 1998–2007 and Pioneer 85G46
in 2008–2011) is planted in late May or early June. Irrigation is used to minimize water
stress. Furrow irrigation was used through 2000, and sprinkler irrigation has been used
since 2001. The center two rows of each plot are machine harvested after physiological
maturity. Grain yields are adjusted to 12.5% moisture. Soil samples (0–6 in.) were taken
following harvest in 2010. Soil test P was determined by two methods: Bray-1, because
the historical analyses used this method, and Olsen, because of the high pH in some
treatments.
Results
Grain sorghum yields in 2011 were greater than the 10-year average yields (Table 1).
Nitrogen alone increased yields about 50 bu/a, and P alone increased yields less than
10 bu/a; however, N and P applied together increased yields up to 75 bu/a. Averaged
across the past 10 years, N and P applied together increased yields more than 60 bu/a.
In 2011, 40 lb/a N (with P) produced about 80% of maximum yields, which is slightly
less than the 10-year average. Sorghum yields were not affected by K fertilization, which
has been the case throughout the study period.
40
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Soil Fertility
Soil organic matter was increased by N and P fertilization of grain sorghum from 2.1%
in the unfertilized control up to 2.6% with N and P fertilization (Table 2). Soil test
P was increased by P fertilization from an initial value of ~17 ppm up to >30 ppm.
Without P fertilization, soil test P was reduced with N rates of 120 lb N/a or less, but at
higher N rates, soil test P actually increased from 25 to 28 ppm. This increase in soil test
P without P additions is surprising. We also noticed this trend with the Olsen test. Soil
pH was reduced by N fertilization from 7.8 in the unfertilized control to 6.6 with 200
lb N/a, whereas P applications had no effect on soil pH.
41
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
42
Soil Fertility
Table 1. Effect of nitrogen, phosphorus, and potassium fertilizers on irrigated grain sorghum yields, Tribune, KS, 2002–2011
Fertilizer
Grain sorghum yield
N
P2O5
K2O
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
Mean
-------------- lb/a -------------------------------------------------------------------------------------------- bu/a ------------------------------------------------------------------------------0
0
0
73
80
57
58
84
80
66
64
51
75
69
0
40
0
81
93
73
53
102
97
60
70
51
83
77
0
40
40
82
93
74
54
95
94
65
76
55
88
78
40
0
0
82
92
60
63
102
123
92
84
66
106
88
40
40
0
120
140
112
84
133
146
111
118
77
121
118
40
40
40
121
140
117
84
130
145
105
109
73
125
116
80
0
0
97
108
73
76
111
138
114
115
73
117
103
80
40
0
127
139
103
81
132
159
128
136
86
140
125
80
40
40
131
149
123
92
142
166
126
108
84
138
127
120
0
0
86
97
66
77
101
138
106
113
70
116
98
120
40
0
132
135
106
95
136
164
131
130
88
145
127
120
40
40
127
132
115
98
139
165
136
136
90
147
130
160
0
0
116
122
86
77
123
146
105
108
74
124
109
160
40
0
137
146
120
106
145
170
138
128
92
152
135
160
40
40
133
135
113
91
128
167
133
140
88
151
129
200
0
0
113
131
100
86
134
154
120
110
78
128
117
200
40
0
136
132
115
108
143
168
137
139
84
141
131
200
40
40
143
145
123
101
143
170
135
129
87
152
134
continued
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Means
Nitrogen, lb/a
0
40
80
120
160
200
LSD (0.05)
P2O5-K2O, lb/a
0
40-0
40-40
LSD (0.05)
79
108
119
115
129
131
9
88
124
132
121
134
136
10
68
96
100
96
107
113
11
55
77
83
90
92
98
10
93
121
128
125
132
140
11
91
138
155
156
161
164
9
64
103
123
124
125
131
7
70
104
120
126
125
126
11
52
72
81
82
83
84
5
82
117
132
136
142
141
8
75
107
119
118
124
127
5
94
122
123
6
105
131
132
7
74
105
111
7
73
88
87
7
109
132
130
7
130
151
151
6
101
117
117
5
99
120
116
7
68
80
79
4
111
130
133
6
97
119
119
4
Soil Fertility
Table 1. Effect of nitrogen, phosphorus, and potassium fertilizers on irrigated grain sorghum yields, Tribune, KS, 2002–2011
Fertilizer
Grain sorghum yield
N
P2O5
K2O
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
Mean
-------------- lb/a -------------------------------------------------------------------------------------------- bu/a ------------------------------------------------------------------------------ANOVA (P > F)
Nitrogen
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
Linear
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
Quadratic
0.001
0.001
0.018
0.005
0.004
0.001
0.001
0.001
0.001
0.001
0.001
P-K
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
Zero P vs. P
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
P vs. P-K
0.920
0.694
0.121
0.803
0.578
0.992
0.745
0.324
0.892
0.278
0.839
N × P-K
0.030
0.008
0.022
0.195
0.210
0.965
0.005
0.053
0.229
0.542
0.013
43
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Soil Fertility
Table 2. Selected soil properties (0–6 in.) after long-term (50 years) applications of N
and P fertilizers to irrigated grain sorghum, Tribune, KS, 2010
N
P2O5
OM
Bray 1 P
Olsen P
pH
-------------- lb/a -------------%
---------------------- ppm ---------------------0
0
2.1
11
6
7.8
40
2.3
36
21
7.7
40
0
2.2
13
7
7.7
40
2.4
43
23
7.5
80
0
2.3
14
7
7.1
40
2.4
35
19
7.4
120
0
2.4
9
5
7.2
40
2.5
19
10
7.2
160
0
2.5
28
14
7.1
40
2.6
37
21
6.6
200
0
2.6
25
12
6.6
40
2.6
35
17
6.5
ANOVA (P > F)
Nitrogen
Linear
Quadratic
Phosphorus
N×P
Means
Nitrogen
0 lb/a
40
80
120
160
200
LSD (0.05)
P2O5
0 lb/a
40
LSD (0.05)
44
0.001
0.001
0.821
0.001
0.485
0.109
0.361
0.219
0.001
0.444
0.113
0.658
0.226
0.001
0.392
0.001
0.001
0.435
0.128
0.035
2.2
2.3
2.4
2.4
2.5
2.6
0.1
24
28
24
14
32
30
13
13
15
13
7
17
15
7
7.8
7.6
7.2
7.2
6.9
6.6
0.2
2.3
2.5
0.1
16
34
8
8
18
4
7.2
7.2
0.1
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Soil Fertility
Phosphorus Fertilization of Irrigated Corn
Alan Schlegel
Summary
Phosphorus increased yields more than 60 bu/a in 2011, which was similar to the longterm average. Application of 80 lb/a P2O5 produced maximum yield in 2011, and 97%
of maximum yield was obtained with 40 lb/a P2O5. Across the eight years of the study,
40 lb/a P2O5 produced 93% of maximum yield. Soil test P was maintained by a P fertilizer rate of 40 lb/a P2O5 and increased with higher P rates.
Introduction
This study was initiated in 2004 to determine responses of continuous corn grown
under sprinkler irrigation to phosphorus (P) fertilization. This study complements a
long-term nitrogen (N) and P study by having a wider range of P rates. The study is
conducted on a Ulysses silt loam soil with an inherently high potassium (K) content.
Procedures
This field study is conducted at the Tribune Unit of the Southwest Research-Extension
Center. Fertilizer treatments are 0, 20, 40, 80, and 120 lb/a of P2O5. All P fertilizers
were broadcast by hand in the spring and incorporated before planting. Treatments
were applied to the same plots each year. Nitrogen was uniformly applied to all plots
at 200 lb N/a. The corn hybrids [Pioneer 34N45 (2004 and 2005), Pioneer 34N50
(2006), Pioneer 33B54 (2007), Pioneer 34B99 (2008), DeKalb 61-69 (2009), Pioneer
1173H (2010), and Pioneer 1151XR (2011)] were planted at about 30,000 to
32,000 seeds/a in late April or early May. Hail damaged the 2005, 2008, and 2010
crops. The corn is irrigated to minimize water stress. The center two rows of each
plot are machine harvested after physiological maturity. Grain yields are adjusted to
15.5% moisture. Soil samples (0–6 in.) were taken following harvest in most years and
analyzed for Mehlich-3 P.
Results
Corn yields in 2011 were much greater than the long-term average (Table 1). Phosphorus increased yields more than 60 bu/a, which was similar to the long-term average.
Application of 80 lb/a P2O5 produced maximum yield in 2011, and 97% of maximum
yield was obtained with 40 lb/a P2O5. Across the eight years of the study, 40 lb/a P2O5
produced 93% of maximum yield.
Soil test P was maintained by a P fertilizer rate of 40 lb/a P2O5 and increased with
higher P rates (Table 2). Without P fertilization, soil test P declined from 15 ppm in
2005 to 10 ppm in 2011.
45
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has been archived. Current information is available from http://www.ksre.ksu.edu.
Soil Fertility
Table 1. Grain yield of irrigated corn as affected by phosphorus (P) rate, Tribune, KS,
2004–2011
P2O5 rate
2004 2005† 2006 2007 2008 2009 2010 2011 Average
lb/a
---------------------------------------------- bu/a ---------------------------------------------0
180
118
122
150
98
161
29
184
130
20
191
145
163
200
140
189
49
206
160
40
206
154
187
211
136
211
57
239
175
80
222
163
204
240
144
226
62
246
188
120
222
170
208
235
137
221
64
246
188
LSD (0.05)
15
14
12
20
17
19
12
23
6
ANOVA (P > F)
Year
P rate
0.001
Year × P rate
†
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
Hail on August 19, 2005; August 14, 2008; and July 23, 2010.
Table 2. Soil test phosphorus (P) (Mehlich-3) in the surface soil (0–6 in.) following
annual P applications to irrigated corn, Tribune, KS, 2005–2011
P2O5 rate
2005
2006
2008
2010
2011
lb/a
---------------------------------------------- ppm ---------------------------------------------0
15
12
13
11
10
20
14
15
16
15
11
40
15
15
19
21
16
80
21
22
28
39
34
120
25
37
55
76
52
LSD (0.05)
6
5
6
22
6
ANOVA (P > F)
P rate
46
0.007
0.001
0.001
0.001
0.001
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has been archived. Current information is available from http://www.ksre.ksu.edu.
Soil Fertility
Phosphorus Fertilization of Irrigated Grain
Sorghum
Alan Schlegel
Summary
Phosphorus (P) increased sorghum yields more than 30 bu/a in 2011, which was greater
than the long-term average. Application of 80 lb/a P2O5 produced maximum yield in
2011, and 90% of maximum yield was obtained with 40 lb/a P2O5. Across the eight
years of the study, 20 lb/a P2O5 produced ~95% of maximum yield. Soil test P remained
relatively constant even without the application of P fertilizer and was considerably
increased with P rates of 40 lb/a P2O5 or greater.
Introduction
This study was initiated in 2004 to determine responses of continuous grain sorghum
grown under sprinkler irrigation to P fertilization. This study complements a long-term
nitrogen (N) and P study by having a wider range of P rates. The study is conducted on
a Ulysses silt loam soil with an inherently high potassium (K) content.
Procedures
This field study is conducted at the Tribune Unit of the Southwest Research-Extension
Center. Fertilizer treatments are 0, 20, 40, 80, and 120 lb/a of P2O5. All P fertilizers
were broadcast by hand in the spring and incorporated before planting. Treatments
were applied to the same plots each year. Nitrogen was uniformly applied to all plots
at 200 lb N/a. Sorghum (Pioneer 8500/8505 from 2004–2007 and Pioneer 85G46 in
2008–2011) is planted in late May or early June. Hail damaged the 2005, 2008, and
2010 crops. The grain sorghum is irrigated to minimize water stress. The center two
rows of each plot are machine-harvested after physiological maturity. Grain yields are
adjusted to 12.5% moisture. Soil samples (0–6 in.) were taken following harvest in most
years and analyzed for Mehlich-3 P.
Results
Grain sorghum yields in 2011 were greater than the long-term average (Table 1).
Phosphorus increased yields more than 30 bu/a, which was greater than the long-term
average. Application of 80 lb/a P2O5 produced maximum yield in 2011, and 90% of
maximum yield was obtained with 40 lb/a P2O5. Across the eight years of the study,
20 lb/a P2O5 produced ~95% of maximum yield.
Soil test P remained relatively constant across years even without the application of
P fertilizer (Table 2). Considerable increase in soil test P was observed with P rates of
40 lb/a P2O5 or greater.
47
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has been archived. Current information is available from http://www.ksre.ksu.edu.
Soil Fertility
Table 1. Grain yield of irrigated grain sorghum as affected by phosphorus (P) rate,
Tribune, KS, 2004–2011
P2O5 rate
2004 2005† 2006 2007 2008 2009 2010 2011 Average
lb/a
---------------------------------------------- bu/a ---------------------------------------------0
88
76
124
151
114
120
64
119
107
20
103
99
135
163
135
139
67
138
122
40
104
90
134
172
122
140
72
141
122
80
113
99
142
175
125
144
72
155
128
120
116
96
137
184
130
138
78
152
129
LSD (0.05)
14
16
13
10
23
13
8
16
5
ANOVA (P > F)
Year
P rate
0.009
Year × P rate
†
0.053
0.110
0.001
0.370
0.012
0.014
0.003
0.001
0.001
0.623
Hail on August 19, 2005; August 14, 2008; and July 23, 2010.
Table 2. Soil test P (Mehlich-3) in the surface soil (0–6 in.) following annual P applications to irrigated grain sorghum, Tribune, KS, 2005–2011
P2O5 rate
2005
2006
2008
2009
2010
2011
lb/a
---------------------------------------------- ppm ---------------------------------------------0
12
12
9
10
13
16
20
12
15
16
15
14
16
40
14
16
22
26
30
47
80
19
27
52
52
47
51
120
24
35
95
87
83
90
LSD (0.05)
3
7
19
14
9
18
ANOVA (P > F)
P rate
0.001
48
0.001
0.001
0.001
0.001
0.001
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Weed Science
Weed Control with 9 Tank Mixes of Saflufenacil,
Dimethenamid-P, Atrazine, and Pyroxasulfone
Herbicide in Irrigated Glyphosate-Resistant
Corn
R. Currie and J. Jester
Summary
Pyroxasulfone (experimental number KIH 485) is projected to be labeled for sale by
June of 2012. Although its strengths are grassy weed control, pyroxasulfone tank mixes
seem to provide Palmer amaranth control as well. The degree and duration of control
appears to be contingent on the application rate.
Introduction
As many weed species develop resistance to common herbicide modes of action, labeling new compound novel modes of action becomes even more important. Pyroxasulfone has been exhaustively researched at the Southwest Research-Extension Center in
Garden City, KS, for over a decade with the experimental code name KIH 485. Pyroxasulfone is finally expected to be labeled by June of 2012. Saflufenacil was labeled at the
beginning of the 2011 growing season. The objective of this study was to measure the
effects of various tank mixes of saflufenacil and pyroxasulfone with other known herbicide standards for Palmer amaranth control.
Procedures
Palmer amaranth control was evaluated in the glyphosate-resistant corn variety DKC
64-83 at the Kansas State Research Center located near Garden City, KS. Corn was
planted on May 5, 2011, with preemergence herbicides applied within 24 hours of
planting. Preemergent application conditions of air temperature, soil temperature, wind
speed, relative humidity, and soil moisture were 62ºF, 55ºF, 5 mph, 83%, and adequate,
respectively. Soil was Ulysses silt loam, and organic matter, soil pH, and cation exchange
capacity (CEC) were 1.4%, 8, and 18.4. All herbicide treatments were applied with a
tractor-mounted CO2 pressurized windshield sprayer calibrated to deliver 20 gpa at 30
psi at 4.1 mph. All plots were treated with 32 oz/a of glyphosate to remove any emerged
plants from the plots. Adjuvant and ammonium sulfate (AMS) were added per manufacturer recommendations. The first post-herbicide application was made on June 13,
2011, when corn was 14 in. tall. Air temperature, soil temperature, wind speed, relative
humidity, and soil moisture were 78ºF, 68ºF, 7 mph, 58%, and adequate. The second
post-application herbicide application was made on June 15, 2011, with air temperature, soil temperature, wind speed, relative humidity, and soil moisture at 72ºF, 70ºF, 5
mph, 26%, and adequate. Trial was established as a randomized complete block design
with four replications, and plots were 10 ft by 30 ft. Crop injury and percentage weed
control were visually rated.
49
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Weed Science
Results and Discussion
No crop injury was observed. Palmer amaranth was controlled 95% or better with treatments 3, 6, and 7 at 49 days after planting (DAP) compared with 0 to 13% in untreated
checks. By 113 DAP, only treatments 6 and 7 had greater than 97% control compared
with 0% control in the untreated check (Table 1). Due to extraordinary drought
conditions, corn yield varied widely based on when maximal drought stress occurred.
Although the planting date of this trial produced the highest yields of any near this test
site, the highest yields still ranged from 40 to 50 bu/a. The primary value of pyroxasulfone is as a control agent for grassy weeds; it also appears to have activity on Palmer
amaranth, a small-seed broadleaf weed. Previous work has shown that this result occurs
two out of three years and is dependent on herbicide rate and rainfall. This pattern of
control is consistent with other grass herbicides. In this study, saflufenacil and pyroxasulfone tank mixes appear to provide Palmer amaranth control. The degree and duration
of control appears to be contingent on the rate used. The price of pyroxasulfone has yet
to be determined and will not be static over the next several years, but after a few years,
market forces will establish its value. When the price is known, the economical rate to
use the compound will be more easily determined.
50
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has been archived. Current information is available from http://www.ksre.ksu.edu.
Weed Science
Table 1. Palmer amaranth control 49 and 113 days after planting (DAP)
Treatment Active ingredient
1
Untreated check
2
Dimethenamid-P + saflufenacil
Atrazine
3
Dimethenamid-P + saflufenacil
Glyphosate
Dicamba
4
Dimethenamid-P + saflufenacil
Pyroxasulfone
5
Saflufenacil
Pyroxasulfone
6
Dimethenamid-P + saflufenacil
Pyroxasulfone
Dicamba
Glyphosate
7
Pyroxasulfone
Saflufenacil
Pyroxasulfone
Dicamba
Glyphosate
8
Acetochlor, flumetsulam, clopyralid, dichlormid
Glyphosate
9
Acetochlor, flumetsulam, clopyralid, dichlormid
Glyphosate
LSD (0.10)
1
Rate
15 fl oz/a
1 qt/a
15 fl oz/a
22 fl oz/a
4 oz wt/a
13 fl oz/a
2 oz wt/a
2.5 fl oz/a
2 fl oz/a
13 fl oz/a
2 oz wt/a
3 oz wt/a
22 fl oz/a
2 oz wt/a
1 fl oz/a
1 oz wt/a
3 oz wt/a
22 fl oz/a
1.75 pt/a
24 oz/a
1.75 pt/a
24 oz/a
Timing
A
A
A
A
B
B
A
A
A
A
A
B
B
B
A
A
B
B
B
A
C
B
B
1
% control
49 DAP
113 DAP
0
0
81.3
80
95
90
75
45
80
88
99
99
100
97
85
88
88
86
23
26
A is preemergence, B is 39 DAP, C is 42 DAP.
51
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has been archived. Current information is available from http://www.ksre.ksu.edu.
Weed Science
Weed Control with 15 Herbicide Tank Mixes
of Isoxaflutole, Tembotrione Thiencarbazonemethyl, Atrazine, Trileton, S-metolachlor, and
Mesotrione Herbicide in Irrigated GlyphosateResistant Corn
R. Currie and J. Jester
Summary
No preemergence treatment alone produced sufficient control 49 days after planting
(DAP). With only one exception, all preemergence treatments followed by a postemergence application provided greater than 95% control 106 DAP. All of these treatments
contained more than one herbicide mode of action.
Introduction
With the advent of weeds with herbicide resistance to multiple modes of herbicide
activity, tank mixes have become increasingly complex. Furthermore, a single preemergence application of even a complex mix of modes of herbicide action is seldom sufficient for commercial levels of control. The objective of this study was to test several
preemergence and postemergence tank-mix combinations.
Procedures
Palmer amaranth control was evaluated in the glyphosate-resistant corn variety DKC
64-83 at the Kansas State Research Center located near Garden City, KS. Corn was
planted on May 15, 2011, with preemergence herbicides applied within 24 hours of
planting. Preemergent application conditions of air temperature, soil temperature,
wind speed, relative humidity, and soil moisture were 47ºF, 65ºF, 10 mph, 74%, and
adequate, respectively. Soil was Ulysses silt loam, organic matter, soil pH, and cation
exchange capacity (CEC) were 1.4%, 8, and 18.4. All herbicide treatments were applied
with a tractor-mounted CO2 pressurized windshield sprayer calibrated to deliver 20
gpa at 30 psi and 4.1 mph. All treatments included 32 oz/a of glyphosate to remove any
emerged plants from the plots. Adjuvant and ammonium sulfate (AMS) were added
per manufacturer recommendations. Post-herbicide application was made on June 15,
2011, when corn was 14 in. tall. Post-application conditions of air temperature, soil
temperature, wind speed, relative humidity, and soil moisture were 83ºF, 76ºF, 4 mph,
26%, and adequate, respectively. The trial was established as a randomized complete
block design with four replications. Plots were 10 ft by 30 ft. Crop injury and percentage weed control were visually rated.
Results and Discussion
No crop injury was observed. Palmer amaranth control 49 DAP was greater than 95%
in all but treatments 9, 10, and 14 compared with 0% in untreated checks (Table 1).
With the exception of treatments 8, 9, and 10, all treatments provided greater than 93%
control by 106 DAP. Although yield data was collected due to drought, yield was too
52
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Weed Science
poor for the data to be useful. No preemergence treatment alone produced sufficient
control 49 days after planting (DAP). With only one exception, all preemergence treatments followed by a postemergence application provided greater than 95% control 106
DAP. All of these treatments contained more than one herbicide mode of action.
Table 1. Palmer amaranth control 49 and 106 days after planting (DAP)
Treatment Active ingredient
1
Untreated check
2
Isoxaflutole + thiencarbazone-methyl
Atrazine
Trileton/isoxazoline
Atrazine
3
Isoxaflutole + thiencarbazone-methyl
Atrazine
Glyphosate
4
Isoxaflutole
Atrazine
Trileton/isoxazoline
Atrazine
5
Isoxaflutole
Atrazine
Trileton/isoxazoline
Glyphosate
6
Isoxaflutole
Atrazine
Tembotrine + thiencarbazone-methyl
Glyphosate
7
S-Metolachlor + Atrazine + mesotrione
Mesatrione + metolachlor + glyphosate
8
Dimethenamid-P + saflufenacil
Atrazine
Dicamba
Glyphosate
9
Isoxaflutole + thiencarbazone-methyl
Atrazine
10
Isoxaflutole
Atrazine
11
Tembotrine + thiencarbazone-methyl
Atrazine
Rate
3 oz/a
1 qt/a
3 oz/a
1 pt/a
3 oz/a
1 qt/a
22 oz/a
3 oz/a
1 qt/a
3 oz/a
1 pt/a
3 oz/a
1 qt/a
3 oz/a
22 oz/a
3 oz/a
1 qt/a
3 oz/a
22 oz/a
1.75 qt/a
3.6 pt/a
13 oz/a
1 qt/a
2.5 oz/a
22 oz/a
5 oz/a
1.3 qt/a
5 oz/a
1.3 qt/a
3 oz/a
1
Timing1
A
A
B
B
A
A
B
A
A
B
B
A
A
B
B
A
A
B
B
A
B
A
A
B
B
A
A
A
A
B
qt/a
Palmer amaranth
control, %
49 DAP
106 DAP
0
0
95
95
98
98
95
99
99
99
98
99
98
98
95
88
88
89
85
91
96
B
98
continued
53
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has been archived. Current information is available from http://www.ksre.ksu.edu.
Weed Science
Table 1. Palmer amaranth control 49 and 106 days after planting (DAP)
Treatment Active ingredient
12
Tembotrine + thiencarbazone-methyl
Glyphosate
13
Tembotrine + thiencarbazone-methyl
Atrazine
Glyphosate
14
S-Metolachlor + Atrazine mesotrione
15
Mesotrione + metolachlor
Glyphosate
LSD (0.10)
1
54
A is preemergence, B is 31 DAP.
Rate
3 oz/a
22 oz/a
3 oz/a
1 qt/a
22 oz/a
3 qt/a
3.6 pt/a
Timing1
B
B
B
B
B
A
B
Palmer amaranth
control, %
49 DAP
106 DAP
95
93
99
98
70
96
20
95
96
9
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has been archived. Current information is available from http://www.ksre.ksu.edu.
Weed Science
Weed Control with 21 Tank Mixes
of Rimsulfuron, Mesotrione, and Atrazine
and Isoxaflutole Herbicide in Irrigated
Glyphosate-Resistant Corn
R. Currie and J. Jester
Summary
Although corn yields were very low due to severe drought, treatments that produced
greater than 95% control 98 days after planting (DAP) had the highest yields. These
treatments all contained some level of atrazine.
Introduction
As their patents expire or approach expiration, products are often augmented with
newer compounds to extend their useful life in the marketplace. The objective of this
study was to determine how rimsulfuron and atrazine effectiveness could be enhanced
with various tank mixes of other products.
Procedures
Palmer amaranth control was evaluated in the glyphosate-resistant corn variety DKC
64-83 at the Southwest Research-Extension Center near Garden City, KS. Corn was
planted on May 20, 2011, with preemergent herbicides applied within 24 hours of
planting under air temperature, soil temperature, wind speed, relative humidity, and
soil moisture of 52ºF, 63ºF, 6 mph, 75%, and adequate, respectively. Soil was Ulysses
silt loam, and organic matter, soil pH, and cation exchange capacity (CEC) were 1.4%,
8, and 18.4. All herbicide treatments were applied with a tractor-mounted CO2 pressurized windshield sprayer calibrated to deliver 20 gpa at 30 psi at 4.1 mph. All plots
were treated with 32 oz/a of glyphosate to remove any emerged plants from the plots.
Adjuvant and ammonium sulfate (AMS) were added per manufacturer recommendations. The first post-herbicide application was made on June 15, 2011, when corn was
14 in. tall and air temperature, soil temperature, wind speed, relative humidity, and soil
moisture were 85ºF, 76ºF, 4 mph, 26%, and adequate, respectively. The second postherbicide application was made on June 29, 2011, with air temperature, soil temperature, wind speed, relative humidity, and soil moisture of 70ºF, 77ºF, 15 mph, 55%,
and adequate. Trial was established as a randomized complete block design with four
replications and plots were 10 by 30 ft. Crop injury and percentage weed control were
visually rated.
Results and Discussion
No crop injury was observed. Palmer amaranth control was 93% or greater with herbicide treatments 3, 7, 9, 10, 17, 20, and 22 at 41 DAP compared with 0% in untreated
checks (Table 1). Only treatments 7, 10, 18, 21, and 22 had greater than 95% control
69 DAP compared with 0% control in the untreated check. All of these treatments
contained atrazine. Treatments 18, 19, and 22 provided 95% or greater control of
Palmer amaranth 98 DAP (data not shown). Although yield data were gathered, they
55
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Weed Science
were not included because the highest-yielding treatment produced only from 28 to 50
bu/a due to historic drought conditions. These highest-yielding treatments also had the
best weed control 98 DAP (data not shown).
Table 1. Palmer amaranth control 41 and 69 days after planting (DAP)
Treatment Active ingredient
1
Untreated check
2
Rimsulfuron
Mesotrione
Glyphosate
Atrazine
3
Rimsulfuron
Mesotrione
Atrazine
Glyphosate
4
Atrazine + S-metolachlor
Rimsulfuron
Mesotrione
5
Atrazine + S-metolachlor
Rimsulfuron
Mesotrione
Glyphosate
6
Rimsulfuron
Isoxaflutole
Atrazine
Rimsulfuron
Mesotrione
7
Rimsulfuron
Isoxaflutole
Rimsulfuron
Mesotrione
Atrazine
8
Rimsulfuron
Isoxaflutole
Atrazine
Rimsulfuron
Mesotrione
Glyphosate
9
Rimsulfuron
Isoxaflutole
Atrazine
Glyphosate
Rate
0.3 oz a/a
1.25 oz a/a
32 fl oz/a
1 lb/a
0.3 oz a/a
1.25 oz a/a
1 lb/a
32 fl oz/a
1 qt/a
0.3 oz a/a
1.25 oz a/a
1 qt/a
0.3 oz a/a
1.25 oz a/a
32 fl oz/a
0.3 oz a/a
0.5 oz a/a
1 lb/a
0.3 oz a/a
1.25 oz a/a
0.3 oz a/a
0.5 oz a/a
0.3 oz a/a
1.25 oz a/a
1 lb/a
0.3 oz a/a
0.5 oz a/a
1 lb/a
0.3 oz a/a
1.25 oz a/a
32 fl oz/a
0.3 oz a/a
0.5 oz a/a
1 lb/a
32 fl oz/a
Timing
B
B
B
B
B
B
B
C
A
B
B
A
B
B
B
A
A
A
B
B
A
A
B
B
B
A
A
A
B
B
B
A
A
A
B
1
% control
41 DAP
69 DAP
0
0
88
93
98
71
85
96
88
88
90
93
99
100
81
84
95
90
continued
56
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Weed Science
Table 1. Palmer amaranth control 41 and 69 days after planting (DAP)
Treatment Active ingredient
10
Atrazine + S-metolachlor
Rimsulfuron
Mesotrione
Glyphosate
11
Mesotrione + metolachlor + glyphosate
12
Rimsulfuron
Mesotrione
13
Rimsulfuron
Mesotrione
14
Rimsulfuron
Thifensulfuron
Mesotrione
15
Rimsulfuron
Mesotrione
Atrazine
16
Rimsulfuron
Mesotrione
Atrazine
17
Rimsulfuron
Thifensulfuron
Mesotrione
Atrazine
18
Rimsulfuron
Mesotrione
Atrazine
Glyphosate
19
Rimsulfuron
Mesotrione
Atrazine
Glyphosate
20
Rimsulfuron
Thifensulfuron
Mesotrione
Atrazine
Glyphosate
21
S-Metolachlor + atrazine + mesotrione
22
S-Metolachlor + atrazine + mesotrione
Glyphosate
LSD (0.10)
1
Rate
1 qt/a
0.3 oz a/a
1.25 oz a/a
32 fl oz/a
3.6 pt/a
0.25 oz a/a
2.25 oz a/a
0.375 oz a/a
2.25 oz a/a
0.25 oz a/a
0.25 oz a/a
2.25 oz a/a
0.25 oz a/a
2.25 oz a/a
1 lb a/a
0.375 oz a/a
2.25 oz a/a
1 lb a/a
0.25 oz a/a
0.25 oz a/a
2.25 oz a/a
1 lb a/a
0.25 oz a/a
2.25 oz a/a
1 lb a/a
32 fl oz/a
0.25 oz a/a
2.25 oz a/a
1 lb a/a
32 fl oz/a
0.25 oz a/a
0.25 oz a/a
2.25 oz a/a
1 lb a/a
32 fl oz/a
3 qt/a
3 qt/a
32 fl oz/a
Timing
B
B
B
C
C
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
BB
A
A
A
BB
A
A
A
A
BB
A
A
BB
1
% control
41 DAP
69 DAP
94
93
0
83
23
90
90
93
84
80
93
96
88
90
93
93
96
99
89
91
93
98
96
99
96
100
17
15
A is preemergence, B is V2-V4, C is 40 DAP, BB is 28 DAP.
57
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has been archived. Current information is available from http://www.ksre.ksu.edu.
Weed Science
Reductions in Corn Leaf Area Induced
by Drought Stress and Level of Irrigation
Impacts Weed Control
R.Currie, N. Klocke, J. Jester
Summary
When irrigation was less than 50% of full irrigation requirements, Palmer amaranth
biomass increased from 6- to 31-fold compared with fully irrigated corn. When irrigation was below 30% of full irrigation requirements, however, Palmer amaranth biomass
was 51 to 82 lb/a. When corn was irrigated with more than 60% of full irrigation, it
was able to compete with Palmer amaranth. Between irrigation levels of 30 and 50%,
Palmer amaranth was able to utilize the remaining water better than the corn. When
irrigation was below 30%, drought severely reduced both weed and crop growth. Fully
irrigated corn yielded from 178 to 203 bu/a, but yield decreased to a minimum of 0
to 3.5 bu when irrigated with less than 30% of full irrigation requirements. Palmer
amaranth biomass was from 9 to 38 lb/a in fully irrigated corn. Palmer amaranth
biomass increased from 1.5- to 4-fold as irrigation decreased to 60% of full irrigation.
Introduction
In a 2011 long-term experiment to measure the dose-response relationship of irrigation
and corn grain yield, corn production was reduced by a severe drought. Corn biomass
and leaf area decreased as irrigation decreased, causing late-season Palmer amaranth
growth. Previous work in hail-injured corn showed that reductions in leaf area index
(LAI) also allowed late-season Palmer amaranth growth (Currie and Klocke, 2008).
Therefore, the objective of this work was to measure corn differentially injured by
drought as indexed by leaf area.
Procedures
Corn was grown in three locations where the objective was to maintain weed-free
conditions. For the five years prior to 2011, weed control was pursued with aggressive
herbicide tank mixes. In 2011, corn first received a preemergence application of glyphosate, atrazine, isoxaflutole, dimethenamid, and saflufenacil at 1, 1.7, 0.031, 0.78, and
0.08 lb ai/a, respectively, followed by postemergence application of fluroxypyr, glyphosate, S-metolachlor, and tembotrione at 0.13, 1, 1.43, and 0.082 lb/a, respectively. Additional postemergence applications of glyphosate at 0.75 lb/a were applied, as needed,
to maintain weed-free conditions at canopy closure. The treatments, replicated four
times, were 100, 84, 71, 55, 42, and 30% of what locally derived models predicted for
non-rate-limited irrigation. As a result, the net irrigation amounts were 18, 14, 10, 7, 4,
and 1 in./a across irrigation treatments, which resulted in 25, 20, 16, 13, 11, and 7 in.
of total water use per acre (evapotranspiration), respectively. Total water use was based
on soil water measurements up to 8 ft, total in-season rainfall, and total net irrigation.
Corn populations for each treatment decreased as level of irrigation decreased . Populations were 32,000, 27,000, 24,500, 22,000 and 9,500, plants/a, respectively.These populations were based on previous models for the level of irrigation to be applied. Corn
58
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Weed Science
LAI was measured as described in a previous study (Currie and Klocke, 2008). Palmer
amaranth biomass samples were taken at corn harvest.
Results and Discussion
The fully irrigated corn yielded from 178 to 203 bu/a. Grain yield decreased linearly
at all locations, to a minimum of 0 to 3.5 bu/a when irrigated with less than 30% of
full irrigation requirements. Palmer amaranth biomass was from 9 to 38 lb/a in fully
irrigated corn. Palmer amaranth biomass increased from 1.5- to 4-fold as irrigation
decreased to 60% of full irrigation. At all three locations, when irrigation was less than
50% of full irrigation requirements, Palmer amaranth biomass increased from 6- to
31-fold compared with fully irrigated corn; however, when irrigation was below 30%
of full irrigation requirements, Palmer amaranth biomass was 51 to 82 lb/a. Although
corn populations were reduced to match reduced irrigation levels, reducing crop water
stress enough to prevent corn leaf loss due to drought was impossible. Severe reduction
in the corn canopy allowed late-season Palmer amaranth to emerge.
In our previous study, simple linear models of corn LAI reduced by hail predicted
corn yield loss well, with R-squared values well above 0.94 (Currie and Klocke, 2008).
Simple linear models of LAI were also predictive of corn yield loss in this study, with
R-squared values greater than 0.99. We advise using this data with caution because
although it is based on two locations, we used regressions of only 3 points; therefore,
the results should be considered only a starting point for future research. Although the
previous work showed a strong linear relationship between corn LAI influenced by hail
injury and Palmer amaranth biomass, no relationship could be shown using this limited
dataset for corn injured by drought stress. When corn was irrigated with more than
60% of full irrigation, it was able to compete with Palmer amaranth. With irrigation
levels from 30 to 50%, Palmer amaranth was able to utilize the remaining water better
than the corn. When irrigation was below 30%, drought severely reduced both weed
and crop growth.
References
Currie, R.S., and N.L. Klocke, 2008. Impact of Irrigation and Hail on Palmer
Amaranth (Amaranthus Palmeri) in Corn. Weed Technology 22(3):448–452.
59
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has been archived. Current information is available from http://www.ksre.ksu.edu.
Weed Science
Kochia Seedling Emergence Patterns
Across the Central Great Plains
A. Dille, R. Currie, P. Stahlman, P. Geier, J.D. Riffel, R. Wilson,
G. Sbatella, P. Westra, A. Kniss, M. Moechnig, R. Cole
Summary
The rate of kochia emergence was studied and found to be slower in cropland than in
non-cropland environments. From 70 to 95% of the kochia seedlings emerged between
the first two observation dates across all locations. High seedling emergence occurring
very early in the season emphasizes the need for early weed control; however, the high
number of seedlings that appear in the second flush (from 5 to 30% of the total population) emphasizes the need for extended periods of early season kochia management. Introduction
Kochia has developed resistance to glyphosate herbicide in many parts of the Great
Plains. Detailed studies of the basic biology of this emerging weed problem are scarce.
Timing of control measure applications is largely influenced by date of emergence and
subsequent weed size, but little is known about this aspect of kochia biology. Therefore,
the objective of this study was to measure the timing and duration of kochia seedling
emergence.
Procedures
Emergence patterns of kochia populations in cropland and non-cropland sites were
monitored in 2010 and again in 2011 in Colorado (Fort Collins [irrigated and dryland
cropland]), Kansas (Garden City [cropland], Hays [cropland, non-cropland], Manhattan [non-cropland], Ness City [non-cropland], and Stockton [non-cropland]),
Nebraska (Mitchell [non-cropland] and Scottsbluff [non-cropland]), Wyoming (Lingle
[non-cropland]), and South Dakota [cropland]. Quadrats (0.25 to 1-m2) were marked
in which weekly observations of emergence were documented and emerged seedlings
were removed by hand or sprayed with glyphosate. Observations were initiated as early
as March 2 and continued through July 30 or until no new emergence was evident on
consecutive observation dates. Results and Discussion
Total season population densities varied among locations and ranged from as few as
10 to almost 332,000 seedlings/m2 (Table 1). Earliest observed emergence occurred
soon after March 2 across locations in 2010 and occurred even earlier in 2011 (Table
2). Although the calendar dates shift from March to April as location moves from
south to north, the growing degree days (GDD) for 10% cumulative kochia emergence
based on air temperatures since January 1 revealed that fewer GDD were needed before
seedling emergence occurred in the north than in the south. This result may indicate a
lower critical temperature for kochia in more northern latitudes. In general, the rate of
kochia emergence was slower in cropland than in non-cropland environments. From 70
to 95% of the kochia seedlings emerged between the first two observation dates across
all locations. High seedling emergence very early in the season emphasizes the need for
60
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Weed Science
early weed control, and the high number of seedlings that appear in the second flush
(from 5 to 30% of the total population) emphasizes the need for extended periods of
early season kochia management. Table 1. Mean density and range (low and high) of maximum kochia emergence
(number/m2) observed across locations, sites, and years
Maximum kochia emergence
Location
Site
Year
Mean
Low
High
-------------------- no./m2 -----------------Lingle, WY
West
2010
5950
341
12723
West
2011
2152
1369
2941
East
2011
65
37
96
Mitchell, NE
NC
2010
11074
6234
15422
2011
18218
16496
19854
Scottsbluff, NE
NC
2010
8480
2964
12291
2011
4780
4140
6322
Stockton, KS
NC
2010
297
91
584
2011
42
29
63
Manhattan, KS
NC
2011
1463
414
3296
Hays, KS
Crop
2010
451
149
692
Crop
2011
21415
13390
32980
NC
2010
331975
310500
379100
NC
2011
68140
61560
75930
Garden City, KS
notill
2010
10
4
22
notill
2011
58
21
135
tilled
2011
86
17
193
61
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Weed Science
Table 2. Predicted cumulative growing degree days (GDD) and corresponding calendar
date for start (10%) and duration (10 to 90%) of kochia emergence across locations and
sites in 2010 and 2011
GDD
Calendar
duration
Year
Location
Site
GDD to 10%
date
(10 to 90%)
2010 Lingle, WY
West
76
3/21
115
Mitchell, NE
No crop
84
3/17
372
Scottsbluff, NE
No crop
69
3/15
346
Stockton, KS
No crop
282
4/3
61
Hays, KS
Crop
238
3/18
127
No crop
137
3/31
36
Garden City, KS
No-till crop
283
3/31
773
2011
Lingle, WY
Mitchell, NE
Scottsbluff, NE
Stockton, KS
Manhattan, Ks
Hays, KS
Garden City, KS
62
West
East
No crop
No crop
No crop
No crop
Crop
No crop
No-till crop
Tilled crop
109
657
102
99
267
174
136
110
292
460
3/10
5/22
3/12
3/2
3/21
3/15
3/10
2/24
3/22
4/9
70
112
77
181
733
130
54
300
972
509
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has been archived. Current information is available from http://www.ksre.ksu.edu.
Weed Science
Alternatives to Glyphosate for Kochia Control
in Dryland No-Till Corn
P.W. Stahlman, D.A. Brachtenbach, P.W. Geier, and S.S. Reddy
Summary
The greatest and most consistent season-long kochia control, averaged across three
experiments, was achieved with preemergence-applied Balance Flexx + Aatrex 4L at
4 + 20 oz/a or Lumax at 2.5 qt/a. Postemergence treatments of Laudis (3 oz/a) or
Impact (0.75 oz/a) + Aatrex 4L at 8 oz + 1% w/v AMS and 1% v/v MSO were similarly
effective as several preemergence treatments at mid-season, but end-of-season control
declined considerably. This study indicates the need for a preplant or preemergence
application followed by an in-crop postemergence herbicide treatment to obtain maximum kochia control.
Introduction
The widespread presence of glyphosate-resistant kochia throughout western Kansas
underscores the need for alternatives to glyphosate for weed control in corn. Our
objective was to compare the performance of several herbicide treatments other than
glyphosate for kochia control in no-till corn.
Procedures
Experiments were conducted on grower fields (dryland) near Levant, Park, Phillipsburg,
and Shields, KS, in 2011. Each field was naturally infested with kochia that was subsequently confirmed as resistant to glyphosate. Experimental areas received a preplant
burndown treatment prior to corn planting, and treatments were applied preemergence
within 2 days after planting (hybrid of grower’s choice) by the farm operator. Spray
volume was 15 gal/a at Levant and 12.7 gal/a at Park, Phillipsburg, and Shields. Postemergence treatments were applied at the V5 corn growth stage at Levant when kochia
was 1 to 6 in. tall, V4 corn growth stage at Park when kochia was 3 to 6 in. tall, V2 corn
stage at Phillipsburg when kochia was 0.5 to 1.5 in. tall, and V4 growth stage at Shields
when kochia was 3 to 4 in. tall. Kochia density ranged from 5 to 10 plants/yd2 at Park
and more than 100 plants/yd2 at Phillipsburg. Treatment costs include herbicides and
adjuvants (10% over dealer cost), but not application or program discounts or rebates.
Corn in the Park and Shield trials was harvested for silage because of drought, and grain
yields of the Levant and Phillipsburg trials are not reported.
Results and Discussion
Averaged across experiments, all but four preemergence treatments controlled kochia
90% or greater at 31 ± 3 days after planting (DAP) (Table 1). Among this group of
treatments, Harness Xtra at 2.3 qt/a was less effective than Balance Flexx + Aatrex 4L
at 4 + 20 oz/a or Lumax at 2.5 qt/a (90 vs. 98% control), but Harness Xtra was similarly effective as Fierce at 4 oz/a (93%), Clarity + 2,4-D LV4 at 16 + 8 oz/a (94%),
and Degree Xtra at 3 qt/a (96%). Verdict at 18 oz/a, Anthem at 7 oz/a, SureStart or
TripleFlex at 1 qt/a, and Valor SX at 3 oz/a were 10 to 23% less effective than Harness
Xtra, the lowest of the top-performing treatments. At 50 ± 3 DAP, only preemergence63
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Weed Science
applied mixtures of Balance Flexx plus Aatrex 4L at 4 + 20 oz/a, Lumax at 2.5 qt/a,
and Degree Xtra at 3.0 qt/a controlled kochia 90% or greater (Table 2). Clarity +
2,4-D LV4 was slightly less effective at 86%. Postemergence-applied Laudis (3 oz/a) or
Impact (0.75 oz/a) mixed with 8 oz/a Aatrex 4L along with AMS and MSO provided
87% kochia control. Mixing Aatrex 4L with Laudis enhanced control significantly
compared with Laudis alone. Kochia control with most treatments, especially those
without atrazine, declined significantly at the end of the season compared with midseason ratings (data not shown); only Balance Flexx plus Aatrex 4L and Lumax treatments maintained control above 80%. Although postemergent applications of Laudis or
Impact plus Aatrex 4L and MSO were similarly effective as the most effective preemergence treatments at mid-season, end-of-season control with those two treatments was
less than 65%. Herbicide treatment costs ranged from as low as $7.91 up to $42.75
per acre. Correlation between treatment cost and kochia control was poor (r = 0.35
or less) at each rating. The greatest and most consistent season-long control averaged
across experiments was achieved with Balance Flexx + Aatrex at 4 + 20 oz/a at a cost of
$21.30/a. Lumax provided similar season-long control as Balance Flexx + Aatrex but at
considerably higher cost.
Lack of complete or nearly complete kochia control with the preemergence herbicides
tested in this study supports the recommendations of K-State weed scientists that
producers use a preplant or preemergence herbicide treatment followed by an in-crop
postemergence herbicide treatment to obtain maximum kochia control.
Table 1. Kochia control in corn 31 ± 3 days after preemergence herbicide application, 2011
Herbicide treatment
Rate/a
Cost/a1
Park
Phillipsburg Shields
Levant
Mean
-------------------------------------- % -----------------------------------Clarity + 2,4-D LV4
16 + 8 oz
$12.17
95
99
89
-94
Verdict
18 oz
$29.75
65
85
99
-83
Balance Flexx + Aatrex 4L
4 + 20 oz
$21.30
99
100
100
95
98
Lumax
2.5 qt
$42.75
98
98
100
95
98
Harness Xtra
2.3 qt
$33.14
88
91
100
83
90
Degree Xtra
3.0 qt
$31.47
97
96
100
92
96
SureStart or TripleFlex
1 qt
$19.86
55
68
88
-70
Valor SX
3 oz
$17.12
76
81
79
-79
Fierce
4 oz
--2
95
83
99
-93
Anthem
7 oz
--2
79
73
93
58
75
LSD (0.05)
10
10
3
2
7
1
2
64
Listed costs are approximate and do not include application or reflect program discounts or rebates.
Product price not yet established.
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Weed Science
Table 2. Kochia control in corn 50 ± 3 days after preemergence or 19 ± 3 days after postemergence herbicide
application, 2011
Herbicide treatment1
Rate/a
Cost/a2
Park
Phillipsburg Shields
Levant
Mean
--------- Preemergence application ----------------------------------------------- % -----------------------------------Clarity + 2,4-D LV4
16 + 8 oz
$12.17
97
78
83
-86
Verdict
18 oz
$29.75
68
53
85
-69
Balance Flexx + Aatrex 4L
4 + 20 oz
$21.30
92
99
99
95
96
Lumax
2.5 qt
$42.75
89
97
99
91
94
Harness Xtra
2.3 qt
$33.14
60
73
97
80
77
Degree Xtra
3.0 qt
$31.47
79
94
99
88
90
SureStart or TripleFlex
1 qt
$19.86
58
89
58
-68
Valor SX
3 oz
$17.10
83
58
65
-68
3
Fierce
4 oz
-73
64
95
-78
3
Anthem
7 oz
-87
92
84
58
80
--------Postemergence application --------Laudis + AMS + MSO
3 oz + 1%
+ 1%
Laudis + Aatrex 4L
3 + 8 oz +
+ AMS + MSO
1% + 1%
Impact + Aatrex 4L
0.75 + 8 oz
+ AMS + MSO
+ 1% + 1%
LSD (0.05)
$19.05
93
74
63
76
77
$19.89
93
90
85
78
87
$18.54
89
95
80
86
87
9
15
7
11
9
The Laudis, Laudis + Aatrex 4L, and Impact + Aatrex 4L treatments were applied postemergence without benefit of preemergent herbicide. All
other treatments were applied preemergence. AMS, ammonium sulfate; MSO, methylated seed oil.
2
Listed costs do not include application or reflect program discounts or rebates.
3
Product price not yet established.
1
65
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has been archived. Current information is available from http://www.ksre.ksu.edu.
Weed Science
Regional Studies on Kochia Management
without Glyphosate
P.W. Stahlman, P.W. Geier, S.S. Reddy, R.S. Currie, B.L. Olson,
C.R. Thompson, J.L. Jester, A. Helm, P. Westra, R.G. Wilson,
G.M. Sbatella, P. Jha, A.R. Kniss, and J.M. Tichota
Summary
Tank mixtures of preemergence-applied Clarity (dicamba) and 2,4-D LV4 (2,4-D ester)
at 8 oz + 8 oz/a or 16 oz + 16 oz/a provided the greatest and most consistent kochia
control of 97 and 98%, respectively, for 5 to 6 weeks after treatment (WAT). Postemergence-applied Gramoxone Inteon (paraquat) at 48 oz/a plus Aatrex 4L (atrazine)
at 16 oz/a or Linex 4L (linuron) at 24 oz/a controlled kochia 90 and 87%, respectively,
at 3 to 4 WAT averaged across eight trials. No other treatment controlled kochia by as
much as 85%.
Introduction
Confirmed glyphosate resistance in multiple kochia (Kochia scoparia) populations in
western Kansas prompted the need to investigate alternatives to glyphosate for control
of kochia.
Procedures
Separate field trials comparing standardized preemergence or postemergence herbicide
treatments were conducted at one or more locations in Colorado, Kansas, Montana,
Nebraska, and Wyoming to evaluate kochia control effectiveness in spring fallow or
prior to crop planting. Only one of the two trials (PRE or POST) was conducted at
some locations. Preemergence herbicides were applied in March or April 2011, depending on location, and postemergence treatments were applied along with appropriate
adjuvants when the majority of kochia plants were 1–4 in. tall.
Results and Discussion
Preemergence-applied Warrant (encapsulated acetochlor) at 2 qt/a, Valor (flumioxazin) at 3 oz/a, and Tripleflex (acetochlor & flumetsulam & clopyralid) at 1 qt/a
controlled kochia poorly (<40% in 4 trials) at 5 to 6 WAT (Table 1). Mean kochia
control with Verdict (saflufenacil & dimethenamid) at 15 oz/a, Balance Flexx (isoxaflutole) at 5 oz/a, Harness Xtra (acetochlor & atrazine) at 2.3 qt/a, and Spartan (sulfentrazone) at 6 oz/a ranged from 60 to 80% in increasing sequential order. Tank mixtures
of preemergence Clarity and 2,4-D LV4 at 8 oz + 8 oz/a or 16 + 16 oz/a provided
the greatest and most consistent kochia control of 97 and 98%, respectively. Postemergence-applied Gramoxone Inteon at 48 oz/a plus Aatrex 4L at 16 oz/a or Linex
4L at 24 oz/a controlled kochia 90 and 87%, respectively, at 3 to 4 WAT, averaged
across eight trials (Table 2). No other treatment controlled kochia by as much as 85%.
Mixtures of Laudis (tembotrione) at 3 oz/a or Impact (topramezone) at 0.75 oz/a in
combination with Aatrex 4L at 8 oz/a, and Sharpen (saflufenacil) at 1 oz/a plus Aatrex
4L at 12 oz/a controlled kochia 79 to 83%. Timing of control assessments varied among
66
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Weed Science
locations, making time comparisons difficult because of different numbers of trials with
similar times of evaluation. Control percentages between most treatments varied widely
both within locations and especially between locations, likely because of differing environmental conditions. Kochia control with Roundup PowerMax (glyphosate) at
32 oz/a was less than 30% in each of four Kansas trials, 43% in one Colorado trial, 82%
in one Montana trial, and 93 and 96% in one Nebraska and a second Colorado trial.
Table 1. Kochia control 5 to 6 weeks after preemergence application in early spring
averaged across four trials in Kansas, 2011
Herbicide treatment
Product/a
Cost/a1
Control, %1
Verdict
15 fl oz
$24.90
58cd2
Balance Flexx
5 fl oz
$24.00
70bc
Harness Xtra 6.0
2.3 qt
$11.94
73bc
Warrant
2.0 qt
$17.00
23e
Valor SX
3 fl oz
$17.10
29e
TripleFlex
1 qt
$19.59
46d
Spartan
6 fl oz
$14.64
79b
Clarity + 2,4-D LV4
8 oz + 8 oz
$ 6.64
97a
Clarity + 2,4-D LV4
16 oz + 16 oz
$13.28
98a
1
2
Listed costs are approximate and do not reflect program discounts or rebates.
Means followed by the same letter are not significantly different.
67
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Weed Science
Table 2. Kochia control 3 to 4 weeks after application averaged across eight trials in
Kansas (4), Colorado (2), Montana (1), and Nebraska (1), 2011
Herbicide treatment1
Rate, oz/a + % v/v
Cost/a2
Control, %3
Roundup PowerMax
32
$5.80
48h
Distinct + NIS
4 + 0.5%
$15.07
65fg
Distinct + 2,4-D LV4 + NIS
4 + 8 + 0.5%
$16.21
67efg
Sharpen + 2,4-D LV4 + MSO
1 + 8 + 1%
$10.00
73def
Sharpen + Aatrex 4L + MSO
1 + 12 + 1%
$9.94
79abcd
Laudis + MSO
3 + 1%
$19.17
76bcde
Laudis + Aatrex 4L + MSO
3 + 8 + 1%
$20.59
83abc
Callisto + Aatrex 4L + MSO
3 + 8 + 1%
$17.53
67efg
Impact + Aatrex 4L + MSO
0.75 + 8 + 1.5%
$21.86
80abcd
Starane NXT
14 + 0.5%
$8.81
60gh
Huskie + NIS
15 + 0.5%
$12.67
74cdef
Rage D-Tech + MSO
32 + 2%
$12.17
52h
Linex 4L + Aatrex 4L + COC
24 + 16 + 1%
$16.69
77bcde
Gramoxone Inteon + Aatrex 4L + COC
48 + 16 + 1%
$14.91
90a
Gramoxone Inteon + Linex 4L + COC
48 + 24 + 1%
$27.49
87ab
All treatments included ammonium sulfate. NIS, non-ionic surfactant; MSO, methylated seed oil; COC, crop oil
concentrate.
2
Listed costs are approximate and do not reflect program discounts or rebates.
3
Means followed by the same letter are not significantly different.
1
68
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Acknowledgments
The staffs of the Southwest Research-Extension Center and Kansas State University appreciate and acknowledge the following companies, foundations, and individuals for their support of the research that has been
conducted in the past year.
Donations
BASF Corp.
Bayer Chemical
CPS – Crop Production Services
DeKalb Genetics Corp.
Dodge City Coop
Drussel Seed
Grant Support
AgXplore Inc.
BASF Corp.
Bayer CropScience
Dow AgroSciences
DuPont Ag Products
Fluid Fertilizer Foundation
Gowan Company
Great Plains Canola Association
Helena Chemical Company
International Plant Nutrition
Institute
Ehmke Seeds
Farm Credit of Southwest Kansas
Green Cover Seed
Garden City Coop
Helena Chemical
Kansas Wheat Alliance
Monsanto Company
Pioneer Hi-Bred Intl.
Sharp Brothers Seed
Triumph Seed
Kansas Grain Sorghum
Commission
Kansas Water Authority
Kansas Wheat Commission
National Crop Insurance Services
National Sunflower Association
Nutrecology Inc.
Stoller Enterprises Inc.
Syngenta
Tessenderlo Kerley Inc.
United Sorghum Checkoff
Program
U.S. Canola Association
USDA/ARS
USDA Canola Project
USDA/Ogallala Aquifer Project
USDA Risk Management Agency
Valent BioSciences
Winfield Solutions
Cooperators/Collaborators
Colorado State University
Dodge City Community College
Kansas Division of Water
Resources
Kansas Water Office
Performance Tests
AgriPro Seeds Inc.
AGSECO Inc.
Allied
Asgrow Seed Company
Channel
Cimarron USA
Colorado Ag. Exp. Stn.
Croplan Genetics
Dairyland Seeds
DeKalb
Drussel Seed & Supply
eMerge
Ehmke Seed
Kansas State University Research
Foundation
Groundwater Management
Districts
Sentek Inc.
South Dakota State University
Sprout Software
Texas A&M University
University of Nebraska
University of Wyoming
USDA/ARS, Bushland, Lubbock,
and Weslaco, TX; Akron, CO
Fontanelle
Forage Genetics
Garst Seed Company
Golden Harvest
Kansas Ag. Exp. Stn.
LG Seeds
Midland Seeds
Monsanto Company
Mycogen Seeds
NC+ Hybrids
Northrup King
PGI
Phillips
Pioneer Hi-Bred Intl.
Producers
Schillinger
Scott Seed
Stine Seed Farms
Syngenta Sorghum Lines
Triumph Seed Company Inc.
Watley
WestBred
W-L Research
69
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Herbicide Premix Appendix
Herbicide Premixes1,2
Product (Manufacturer)
Accurate/Extra (Cheminova)
Affinity BroadSpec (DuPont)
Affinity TankMix (DuPont)
Agility SG (DuPont)
Ally Extra SG (DuPont)
Authority Assist (FMC)
Authority First (FMC)
Authority MTZ (FMC)
Authority XL (FMC)
Banvel K + Atrazine (Arysta)
Basis (DuPont)
Basis Blend (DuPont)
Bicep II Magnum (Syngenta)
Bicep Lite II Magnum (Syngenta)
Bison (Winfield)
Boundary (Syngenta)
Brash (Winfield)
Breakfree ATZ (DuPont)
Breakfree ATZ Lite (DuPont)
Bromox + Atrazine (MicroFlo)
Brozine (Platte Chemical)
Buctril + Atrazine (Bayer)
Bullet (Monsanto)
Callisto Xtra (Syngenta)
Camix (Syngenta)
Canopy (DuPont)
Canopy EX (DuPont)
Capreno (Bayer)
Chaparral (Dow AS)
Charger Max ATZ (Winfield)
Charger Max ATZ Lite (Winfield)
Chism (Cheminova)
Cimarron Max (DuPont)
Cimarron Plus (DuPont)
Cimarron Xtra (DuPont)
Cinch ATZ (DuPont)
Cinch ATZ Lite (DuPont)
Clearmax (BASF)
Confidence Xtra (Winfield)
Confidence Xtra 5.6L (Winfield)
Corvus (Bayer)
Crossbow (Dow)
Curtail (Dow)
Degree Xtra (Monsanto)
Dicamba K + Atrazine (MicroFlo)
Ingredients
37.5% thifensulfuron, 18.8% tribenuron, and 15% metsulfuron
25% thifensulfuron (Harmony) and 25% tribenuron (Express)
40% thifensulfuron (Harmony) and 10% tribenuron (Express)
4.7% thifensulfuron (Harmony), 2.4% tribenuron (Express), 1.9% metsulfuron (Ally),
and 58% dicamba (Banvel)
27.3% thifensulfuron, 13.6% tribenuron (Harmony Extra), and 10.9% metsulfuron (Ally)
3.33 lb sulfentrazone (Spartan) and 0.67 lb imazethapyr (Pursuit)
62.1% sulfentrazone (Spartan) and 7.9% cloransulam (FirstRate)
18% sulfentrazone (Spartan) and 27% metribuzin (Sencor)
62% sulfentrazone (Sparton) and 7.8% chlorimuron (Classic)
1.1 lb potassium salt of dicamba and 2.1 lb atrazine per gal
50% rimsulfuron and 25% thifensulfuron (Harmony)
20% rimsulfuron (Resolve) and 10% thifensulfuron (Harmony)
3.1 lb atrazine and 2.4 lb S-metolachlor (Dual II Magnum) per gal
2.67 lb atrazine and 3.33 lb S-metolachlor (Dual II Magnum) per gal
2 lb bromoxynil (Moxy) and 2 lb MCPA per gal
5.25 lb S-metolachlor (Dual Magnum) and 1.25 lb metribuzin (Sencor) per gal
1 lb dicamba and 2.87 lb 2,4-D amine per gal
3 lb acetochlor + 2.25 lb atrazine per gal
4 lb acetochlor + 1.5 lb atrazine per gal
1 lb bromoxynil and 2 lb atrazine per gal
1 lb bromoxynil and 2 lb atrazine per gal
1 lb bromoxynil (Buctril) and 2 lb atrazine per gal
2.5 lb microencapsulated alachlor (Micro-Tech) and 1.5 lb atrazine per gal
0.5 lb mesotrione (Callisto) and 3.2 lb atrazine (AAtrex 4L)
3.3 lb S-metoloachlor (Dual II Magnum) and 0.33 lb mesotrione (Callisto) per gal
64.3% metribuzin and 10.7% chlorimuron (Classic)
22.7% chlorimuron (Classic) and 6.8% tribenuron (Express)
2.88 lb tembotrione (Laudis) and 0.57 lb thiencarbazone per gal
0.525% aminopyralid (Milestone) and 0.0945% metsulfuron (Ally)
3.1 lb atrazine and 2.4 lb S-metolachlor (Dual II Magnum) per gal
2.67 lb atrazine and 3.33 lb S-metolachlor (Dual II Magnum) per gal
48% metsulfuron and 15% chlorsulfuron
1 lb dicamba and 2.87 lb 2,4-D per gal. and 60% metsulfuron co-pack2
48% metsulfuron and 15% chlorsulfuron
30% metsulfuron (Ally) and 37.5% chlorsulfuron (Glean)
3.1 lb atrazine and 2.4 lb S-metolachlor (Cinch) per gal
2.67 lb atrazine and 3.33 lb S-metolachlor (Cinch) per gal
1 lb imazamox (Beyond) per gal. and 4 lb MCPA per gal. co-pack2
4.3 lb acetochlor (Harness) and 1.7 lb atrazine per gal
3.1 lb acetochlor (Harness) and 1.5 lb atrazine per gal
1.88 lb isoxaflutole (Balance Flexx) and 0.75 lb thiencarbazone per gal
2 lb 2,4-D and 1 lb triclopyr (Remedy) per gal
2 lb 2,4-D and 0.38 lb clopyralid (Stinger) per gal
2.7 lb acetochlor (Degree) and 1.34 lb atrazine per gal
1.1 lb potassium salt of dicamba and 2.1 lb atrazine per gal
C.R. Thompson, D.E. Peterson, W.H. Fick, P.W. Stahlman, and R.E. Wolf. “2012 Chemical Weed Control for Field Crops, Pastures, Rangeland, and Noncropland.” Report of Progress 1063, Kansas State University Agricultural Experiment Station and Cooperative Extension Service,
January 2012, p. 17–20.
2
Co-packs consist of individual components packaged in separate containers or compartments and sold together.
1
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This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Herbicide Premix Appendix
Herbicide Premixes1,2
Product (Manufacturer)
Ingredients
Distinct (BASF)
Enlite (DuPont)
20% acid of diflufenzopyr and 50% acid of dicamba (Banvel SGF)
2.85% chlorimuron (Classic), 36.2% flumioxazin (Valor), and 8.8% thifensulfuron
(Harmony)
Envive (DuPont)
9.2% chlorimuron (Classic), 29.2% flumioxazin (Valor), and 2.9% thifensulfuron (Harmony)
1.74 lb S-metolachlor (Dual Magnum), 2.14 lb atrazine, and 1.0 lb IPA salt of glyphosate per gal
Expert (Syngenta)
Extreme (BASF)
0.17 lb ae imazethapyr (Pursuit) and 1.5 lb ae glyphosate per gal
0.75 lb IPA salt of glyphosate (Roundup), 2 lb acetochlor (Harness) and 1.5 lb atrazine per gal
Field Master (Monsanto)
Finesse (DuPont)
62.5% chlorsulfuron (Glean) and 12.5% metsulfuron (Ally)
Finesse Grass & Broadleaf (DuPont) 25% chlorsulfuron (Glean) and 47% flucarbazone (Everest)
Flexstar GT 3.5 (Syngenta)
0.56 lb fomesafen (Flexstar) and 2.26 lb ae glyphosate per gal
ForeFront R&P (Dow)
0.33 lb ae aminopyralid (Milestone) and 2.67 lb ae 2,4-D per gal
FulTime (Dow)
2.4 lb microencapsulated acetochlor (TopNotch) and 1.6 lb atrazine per gal
Fusion (Syngenta)
2 lb fluazifop (Fusilade) and 0.66 lb fenoxaprop (Option II) per gal
Gangster (Valent)
51% flumioxazin (Valor) and 84% cloransulam (FirstRate) co-pack2
GlyMix MT (Dow)
4 lb glyphosate IPA salt and 0.4 lb 2,4-D per gal
G-Max Lite (BASF)
2.25 lb dimethenamid-P (Outlook) and 2.75 lb atrazine per gal
Grazon P&D (Dow)
2 lb 2,4-D and 0.54 lb picloram (Tordon) per gal
Guardsman Max (BASF)
1.7 lb dimethenamid-P (Outlook) and 3.3 lb atrazine per gal
Halex GT (Syngenta)
2.09 lb S-metolachlor (Dual Magnum), 2.09 lb glyphosate, and 0.21 lb mesotrione (Callisto)
per gal
Harmony Extra SG (DuPont)
33.3% thifensulfuron (Harmony) and 16.7% tribenuron (Express)
Harness Xtra (Monsanto)
4.3 lb acetochlor (Harness) and 1.7 lb atrazine per gal
Harness Xtra 5.6L (Monsanto)
3.1 lb acetochlor (Harness) and 2.5 lb atrazine per gal
Hornet WDG (Dow)
18% flumetsulam (Python) and 60% clopyralid salt (Stinger)
Huskie (Bayer)
0.24 lb pyrasulfotole and 1.92 lb bromoxynil (Buctril) per gal
Journey (BASF)
8.13% imazapic (Plateau) and 21.94% glyphosate
Keystone (Dow)
3 lb acetochlor (Surpass) and 2.25 lb atrazine per gal
Keystone LA (Dow)
4 lb acetochlor (Surpass) and 1.5 lb atrazine per gal
Krovar (DuPont)
40% bromacil (Hyvar) and 40% diuron (Karmex)
Laddok S-12 (Sipcam Agro)
2.5 lb bentazon (Basagran) and 2.5 lb atrazine per gal
Landmark (DuPont)
50% sulfometuron (Oust) and 25% chlorsulfuron (Glean)
Lariat (Monsanto)
2.5 lb alachlor (Lasso) and 1.5 lb atrazine per gal
Lexar (Syngenta)
1.74 lb S-metolachlor (Dual II Magnum), 1.74 lb atrazine, and 0.22 lb mesotrione (Callisto)
per gal
Lumax (Syngenta)
2.68 lb S-metolachlor (Dual II Magnum), 0.268 lb mesotrione (Callisto), and 1 lb atrazine
per gal
Nimble (Cheminova)
50% thifensulfuron (Harmony) and 25% tribenuron (Express)
NorthStar (Syngenta)
7.5% primisulfuron (Beacon) and 43.9% sodium salt of dicamba
Olympus Flex (Bayer)
6.75% propoxycarbazone (Olympus) and 4.5% mesosulfuron (Osprey)
Optill (BASF)
17.8% saflufenacil (Sharpen) and 50% imazethapyr (Pursuit)
Orion (Syngenta)
0.033 lb florasulam and 2.34 lb MCPA per gal
Overdrive (BASF)
20% acid of diflufenzopyr and 50% acid of dicamba
Pastora (DuPont)
56.2% nicosulfuron (Accent) and 15% metsulfuron (Ally)
PastureGard (Dow)
1.5 lb ae triclopyr (Remedy) and 0.5 lb ae fluroxypyr (Starane) per gal
Perspective (DuPont)
39.5% aminocyclopyrachlor and 15.8% chlorsulfuron (Glean)
Prefix (Syngenta)
4.34 lb S-metolachlor (Dual Magnum) and 0.95 lb fomesafen (Reflex) per gal
Prequel (DuPont)
15% rimsulfuron (Resolve) and 30% isoxaflutole (Balance)
C.R. Thompson, D.E. Peterson, W.H. Fick, P.W. Stahlman, and R.E. Wolf. “2012 Chemical Weed Control for Field Crops, Pastures, Rangeland, and Noncropland.” Report of Progress 1063, Kansas State University Agricultural Experiment Station and Cooperative Extension Service,
January 2012, p. 17–20.
2
Co-packs consist of individual components packaged in separate containers or compartments and sold together.
1
71
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Herbicide Premix Appendix
Herbicide Premixes1,2
Product (Manufacturer)
Pulsar (Syngenta)
Pursuit Plus (BASF)
Rage D-Tech (FMC)
Range Star (Albaugh)
Rave (Syngenta)
Ready Master ATZ (Monsanto)
Realm Q (DuPont)
Redeem R&P (Dow)
Report Extra (Cheminova)
Require Q (DuPont)
Resolve Q ( DuPont)
Rezult B&G (BASF)
Sahara (BASF)
Sequence (Syngenta)
Shotgun (United Agri Products)
Sonic (Dow)
Spartan Charge (FMC)
Spirit (Syngenta)
Status (BASF)
Steadfast ATZ (DuPont)
Steadfast Q (DuPont)
Starane NXT (FMC)
Starane Plus Salvo (UAP)
Starane Plus Sword (UAP)
Stout (DuPont)
Stratos (Gharda)
Streamline (DuPont)
SureStart (Dow)
Surmount (Dow)
Synchrony XP (DuPont)
TNT Broadleaf (Gowan)
Tordon RTU (Dow)
TripleFlex (Monsanto)
Valor XLT (Valent)
Velpar AlfaMax (DuPont)
Velpar AlfaMax Gold (DuPont)
Verdict (BASF)
Viewpoint (DuPont)
WeedMaster (NuFarm)
Weld (Winfield)
WideMatch (Dow)
Yukon (Gowan)
Ingredients
0.73 lb ae dicamba (Banvel) and 0.95 lb ae fluroxypyr (Starane) per gal
2.7 lb pendimethalin (Prowl) and 0.2 lb imazethapyr (Pursuit) per gal
0.13 lb carfentrazone (Aim) and 3.93 lb ae 2,4-D ester per gal
1 lb dicamba and 2.87 lb 2,4-D amine per gal
8.8% triasulfuron (Amber) and 50% dicamba (Banvel)
2.0 lb glyphosate IPA salt and 2.0 lb atrazine per gal
7.5% rimsulfuron (Resolve) and 31.25% mesotrione (Callisto)
2.25 lb triclopyr (Remedy Ultra) and 0.75 lb clopyralid (Stinger)
62.5% chlorsulfuron (Glean) and 12.5% metsulfuron (Ally)
6.25% rimsulfuron (Resolve) and 52.9% dicamba
18.4% rimsulfuron (Resolve) and 4% thifensulfuron (Harmony)
4 lb bentazon (Basagran) per gal. and 1 lb sethoxydim (Poast Plus) per gal. co-pack2
7.8% imazapyr (Arsenal) and 62.2% diuron (Karmex)
3 lb S-metolachlor (Dual Magnum) and 2.25 lb ae glyphosate per gal
2.25 lb atrazine and 1 lb iso-octyl ester of 2,4-D per gal
62.1 % sulfentrazone (Spartan) and 7.9% cloransulam (FirstRate)
3.15 lb sulfentrazone (Spartan) and 0.35 lb carfentrazone (Aim) per gal
42.8% primisulfuron (Beacon) and 14.2% prosulfuron (Peak)
16% acid of diflufenzopyr, 44% sodium salt of dicamba, and isoxadifen safener
2.7% nicosulfuron (Accent), 1.3% rimsulfuron (Resolve), and 85.3% atrazine
25.2% nicosulfuron (Accent) and 12.5% rimsulfuron (Resolve)
0.58 lb fluroxypyr (Starane) and 2.33 lb bromoxynil per gal
0.75 lb fluroxypyr (Starane) and 3 lb 2,4-D (Salvo) per gal
0.71 lb fluroxypyr (Starane) and 2.84 lb MCPA (Sword) per gal
67.5% nicosulfuron (Accent) and 5% thifensulfuron (Harmony)
1.1 lb potassium salt of dicamba and 2.1 lb atrazine per gal
39.5% aminocyclopyrachlor and 12.6% metsulfuron methyl (Ally)
3.75 lb acetochlor (Surpass), 0.12 lb flumetsulam (Python), and 0.29 lb ae clopyralid (Stinger)
per gal
0.67 lb picloram (Tordon) and 0.67 lb fluroxypyr (Starane)
21.5% chlorimuron (Classic) and 6.9% thifensulfuron (Harmony)
50% thifensulfuron (Harmony) and 25% tribenuron (Express)
3% acid equivalent picloram (Tordon) and 11.2% 2,4-D ae per gal
3.75 lb acetochlor (Harness), 0.12 lb flumetsulam (Python), and 0.29 lb ae clopyralid
(Stinger) per gal
30% flumioxazin (Valor) and 10.3% chlorimuron (Classic)
35.3% hexazinone (Velpar) and 42.4% diuron (Karmex)
23.1% hexazinone (Velpar) and 55.4% diuron (Karmex)
0.57 lb saflufenacil (Sharpen) and 5 lb dimethenamid-P (Outlook) per gal
31.6% imazapyr (Arsenal), 22.8% aminocyclopyrachlor, and 7.3% metsulfuron methyl (Ally)
1 lb dicamba and 2.87 lb 2,4-D amine per gal
1.75 lb MCPA, 0.64 lb fluroxpyr (Starane), and 0.5 lb clopyralid (Stinger) per gal
0.75 lb clopyralid (Stinger) and 0.75 lb fluroxypyr (Starane) per gal
12.5% halosulfuron (Permit) and 55% sodium salt of dicamba
C.R. Thompson, D.E. Peterson, W.H. Fick, P.W. Stahlman, and R.E. Wolf. “2012 Chemical Weed Control for Field Crops, Pastures, Rangeland, and Noncropland.” Report of Progress 1063, Kansas State University Agricultural Experiment Station and Cooperative Extension Service,
January 2012, p. 17–20.
2
Co-packs consist of individual components packaged in separate containers or compartments and sold together.
1
72
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
Jeff Elliott, Research Farm Manager
B.S., University of Nebraska
Jeff joined the staff as an Animal Caretaker III in 1984 and was promoted to Research Farm
Manager in 1989.
John Holman, Cropping Systems Agronomist
B.S., M.S., Montana State University
Ph.D., University of Idaho
John joined the staff in 2006. His research involves crop rotations, forages, and integrated weed
management.
Norman Klocke, Water Resources Engineer
B.S., University of Illinois
M.S., University of Kansas
Ph.D., Colorado State University
Norm joined the staff in 2001. His research emphases include limited irrigation, water conservation, and leaching.
Bertha Mendoza, EFNEP/FNP Area Agent
B.S., Kansas State University
M.S., Fort Hays State University
Bertha joined the staff in October 2009. She delivers nutrition education programs and emphasizes the importance of physical activity for a healthy lifestyle to low-income families from several
cultural backgrounds in southwest Kansas.
Alan Schlegel, Agronomist-in-Charge, Tribune
B.S., Kansas State University
M.S., Ph.D., Purdue University
Alan joined the staff in 1986. His research involves fertilizer and water management in reduced
tillage systems.
Justin Waggoner, Extension Specialist, Beef Systems
B.S., M.S., Animal Sciences and Industry, Kansas State University
Ph.D., Ruminant Nutrition, New Mexico State University
Justin joined the staff in 2007. His extension program focuses primarily on beef cattle and livestock
production.
This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service
has been archived. Current information is available from http://www.ksre.ksu.edu.
FIELD
DAY
2012
Copyright 2012 Kansas State University Agricultural Experiment Station and Cooperative Extension Service. Contents
of this publication may be freely reproduced for educational purposes. All other rights reserved. In each case, give credit
to the author(s), Field Day 2012, Southwest Research-Extension Center, Kansas State University, May 2012. Contribution no. 12-358-S from the Kansas Agricultural Experiment Station.
Chemical Disclaimer
Brand names appearing in this publication are for product identification purposes only. No endorsement is intended,
nor is criticism implied of similar products not mentioned. Experiments with pesticides on nonlabeled crops or target
species do not imply endorsement or recommendation of nonlabeled use of pesticides by Kansas State University. All
pesticides must be used consistent with current label directions. Current information on weed control in Kansas is available in 2012 Chemical Weed Control for Field Crops, Pastures, Rangeland, and Noncropland, Report of Progress 1063,
available from the Distribution Center, Umberger Hall, Kansas State University, or at: www.ksre.ksu.edu/library
(type Chemical Weed Control in search box).
Publications from Kansas State University are available at: www.ksre.ksu.edu
Kansas State University Agricultural Experiment Station
and Cooperative Extension Service
SRP 1070
K-State Research and Extension is an equal opportunity provider and employer.
May 2012
370